Thanks again, that’s great to hear! 
Looking at screenshots from the (Tuya?) app, there is some support for minimum brightness:
It may well be an app-only thing, though.
It may well be an app-only thing, though.
That’s interesting, maybe they exposed it as ZCL-compliant manufacturer channel after all? I’ll check it out, but considering how manufacturers approach Zigbee, I don’t really have huge hopes about it - won’t be surprised if it turns out to be another vendor-specific implementation, not available without developing a custom ZHA device handler. 
Idle question: does zigbee compliance require a device to work with monostable buttons? I can see why they are needed with a dimmer, but not necessarily with an on/off switch.
Similarly, what does the standard require for minimum brightness?
I’m pretty sure that Zigbee compliance is mainly about defining the channels (eg. on/off, power consumption etc) in such a way that it’s possible to use Zigbee hubs from different manufactures, much like in case of ZWave. What’s more, it doesn’t seem to force the manufacturers to implement everything in the compliant way, as the new Aqara switch shows - it’s present on the Zigbee Alliance site with all the documents, exposes basic functionality like on/off and power consumption to be used by Home Assistant without having to use a custom handler, but has the functionality of changing the button type which can be accessed only when connected to Aqara Hub through Aqara app.
That’s a shame, since unless the requirements for certification of Zigbee devices change to enforce proper handling of such a custom features, we will never achieve the same level of seamless experience ZWave ecosystem offers.
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@konpon96, @nickrout If you are ready for a lecture regarding Zigbee compliance, then navigate to the SmartThings Community Forum and ask the question to @JDRoberts. He will give you a detailed answer what you need to know about Zigbee’s compliance requirements.
Some of the features what you are expecting are not necessarily part of the standard. Then companies implementing it through the manufacturer specific options.
Indeed he gave an explanation recently:
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Could you explain how these dimmer switches function? I’m having trouble finding a description of their behavior.
Do the dimmer switches let you use rotary switches to control brightness? (Like this one https://www.amazon.de/-/en/Unitec-40010L-Dimmer-Flush-Mounted-Standard/dp/B007CWAEQY/)
If not, then I assume the dimming can only be done via zigbee, so what effect does pressing the switch have?
Do switch presses always control the attached circuit or do they emit a Zigbee event? I.e. could I have a switch connected to a light but have the physical switch actually cause something else in my HA setup?
Also regarding the 2 way switches/dimmers. I suppose it is possible to close the circuit via the switch and zigbee. This means you could end up with the 2 gang switches in different positions but the connected circuits in the same state (i.e. the lights both on)?
Edit: and since this thread is EU focused, here’s a new seller that seems to have entered the market in the EU. Haven’t heard of anyone using them yet though.
The dimmers can have one or two monostable (doorbell) buttons attached to them, depending on if they are controlling one or two lights. Single press of the button toggles the light, while holding the button down makes it change the brightness gradually from 100% to 0% and then from 0% back to 100%. They remember the setting, so if you turn the light off and then on again, the brightness will be the same as before it was turned off. There is no way to connect a rotary switch to it.
From my tinkering with them I can say that they always control the circuit. They are visible in HA as a dimmable light, so the most you can do is hook on the light’s standard behaviours (toggle, change brightness). That’s not bad though - the fact that the button controls the circuit directly means that the switch won’t go fully dumb when the Home Assistant malfuncitons or goes down.
You’re right about the switches - the fact that they can be controlled both by the button and Zigbee means that the 2 gang switches could end up in different positions, which doesn’t look very well. That’s why I’m waiting for some manufacturer to finally release an in-wall switch that would work with Home Assistant AND the monostable buttons. Aqara switch does support both bistable and monostable ones, but the mode toggle is implemented in a way that can be changed only when paired with Aqara hub - there is no option to do that from Home Assistant.
These iolloi dimmers look interesting. Although they charge quite a lot for their rotary dimmers, the in-wall mounted ones are quite decent with their $45 price tag - especially considering that they have a hardware minimum brightness setting. However, if that’s not required then the Tuya dimmers seem to be much more wallet-friendly option. Would love to see iolloi release a switch though - maybe it would finally be my Holy Grail of Zigbee switches that would work with the monostable buttons. 
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Thanks for the great reply! That really clears a lot up. I didn’t realize the dimmers are designed to work with only monostable buttons.
How is it having such buttons in your house? At least in my experience it’s not common to have monostable buttons indoors. Do people comment on it? Does it take time to get used too (thinking of WAF here).?
I don’t know, since I didn’t finish my HA-based smart home project due to the lack of the in-wall light switches on the market that would be compatible with monostable buttons and ZHA in Home Assistant. As if it wasn’t bad enough, I can’t even continue to look for them due to lack of time. 
At this point I hope that if I finally manage to get back to that project, there will be something on the market that I will be able to use - maybe the group that Apple, Amazon, Google and Zigbee Alliance formed will finally clean up the Zigbee smart house world by then.
I don’t imagine monostable buttons to be difficult to get used to - after all, we make our button pressing decision based on the fact if the light is turned on or off, not on the button’s position. 
The reason I didn’t opt in for mounting the bistable button in-wall switches is purely the aesthetics, or rather the lack of it when the buttons are in the different positions. I can imagine the guests to be confused when they discover that the buttons act like the doorbell ones, but in fact it’s not entirely uncommon to use the monostable buttons to control the light - I’ve seen plenty of these used in the staircases, complete with a timer to turn off the light after some time.
I don’t know why you are obsessed by monostable buttons.
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We have our home full of them for years of experience now, Z-Wave based ones.
And connected to the Fibaro Dimmer 2 modules (OK, a bit more pricey then their Chinese Zigbee counterfeits) they simply work amazing. Also like @konpon96 mentioned shortpress=toggle, longpress=dim up/down, like pretty common monostable button on dimmer behaviour. But they also possess this (absolutely brilliant) self-test/configuration/whatever feature where they check how the connected LED lights behave on the full scale just after a factory reset, after which the dimmer sets and stores the “1%” and “100%” values the lights(s) can handle properly. This way you can immediately use the dimmer correctly without tinkering with any settings. And so even in standalone operation they can be used between the corrected min and max levels. This was worth the extra € for us. Thought is was worth mentioning this on the side, speaking of setting the boundary levels for LED.
Also, the monostable buttons cannot be distinguished from the bistable ones, using the different switch bases from Busch Jaeger on the same switch material on the outside.
Nevertheless I am interested in purchasing some QS-Zigbee-D02-TRIAC-2C-LN modules, the reason I found this thread, for a setup with 8 lamps in the same big room that need to be controlled separately.
I hope within the Zigbee integration I am able to set the minimum levels through Cluster Atributes. We will see when they arrive. To do all of this with the Fibaros is just way too expensive.
Old thread I know but OMG. I’ve been in the controls (industrial) business for 50 years and I’m reading this and I’m thinking what the heck are monostable and bistable buttons??
Never in my life did I ever order a toggle switch and call it bistable nor a momentary switch and call it monostable.
Yea I made my point already regarding terminolgy. Had no idea @konpon96 wasn’t here any more. I often think when I get chastised for replying to an old thread that there is no point to keeping old threads if you are constantly reminded that the thread is old. If the information is still relevant and no one else has spoken of the subject more recently, what’s the harm?