I also have been thinking a bit on this topic and as usual i get them all, perhaps not so smart.
I have RFXtrx433Mhz for cheap sensors in the garden, this is where HA started for me moving from Telldus.
Then for a fishtank control I needed more reliability and introduced Z-wave. Got bored on the Z-wave price tag and got a Sonoff type-E for Zigbee and have a bunch of switches for that.
Now when IKEA launced the Matter/Thread I bought the Sonoff MAX and connected over LAN i ended up with 4 communication protocols… but I also have WiFI Shellys so I guess it’s 5…
I know this is not good from RF perspective but it’s nice to by cheap stuff that fit my use cases no matter what transmittion they use…
Just want to ad another comment… having this set-up is fine but when selling my house I get a bit of concerns. A guy automated a lot and installed stuff with no physical switches. The new owner (who I know) is having a hard time sorting out things, so my learning is that I install stuff with manual switches, keep them on and use smart bulbs and no “built-in switches” that makes life a pain when selling property…
Off-topic comment though…