I have a Sonoff dongle with Zha and it works Like a Charm.
Now I plan to replace my tuya curtain switches for aqara Relais and I see that aqara devices have a proprietary hub. what am I missing out on when I add aqara devices to my Network whithout using the aqara hub? (I dont own one)
For example can I configure a t2 Relais from aqara so that it works with the phisical attached Hardwired Button that even when the zigbee network is unavailable (server down) without using the aqara hub ?
Assuming all devices you have are Zigbee and supported by the Zigbee integration you intend to use, the only thing you afe missing out on is sending your data to China. ;-). Firmware updates are supported in ZHA and Zigbee2MQTT (though they may arrive a little later, I assume).
I do believe adding direct (wireless) links between devices is easier with zigbee2mqtt (and Deconz) than it is with ZHA. The latter should support it too but I never got it working, and others suffered the same fate if I google.
Hardwired links should always work, no matter what.
Exactly why I don’t use people’s hubs, and if they require it then I simply find an alternative that doesn’t need it or build my own.
I have a few Aqara devices and I’ve never used their hub, it’s always been direct to Zigbee and they work fine that way.
I still have some flood sensors running off the hub - this means if they trigger, the hub will alarm as well as HA.
You can do all that (and more) with Home Assistant’s ZHA integration as well but it might be trickier to find and use the right configuration (as you sometimes need to figure out which attributes/entiries, etc…
Suggest reading this related community guide which covers this topic of not using proprietary hubs/bridges:
Also recommend that also read all these other Zigbee guides too to get better understanding and tips: