Hi together
I know this is not a Smartthings problem , but I want to share my expirience with Tuya an matter.
I have a tuya hub connected to smartthings via matter. There I used following devices
Shown in smartthings:
Parkside water valve : works with smartthings
6× Hama thermostat : works with smartthings
2 different mmwave detectors : works via smartthings
Not shown:
Ketotek thermostat ( same hardware like the hama)
Parkside smart button.
So you see most tuya devices are working, bit there are still some devices not working via matter. Maybe this is helpful for someone
Zigbee devices themselves are not individually certified for matter.
So it’s up to each company that builds a “matter bridge“ as to which, if any, specific Zigbee models they will include in the bridging function.
Matter itself does not yet have a “button” Device class, so the matter bridge manufacturer has to convert the button information to either a switch or a scene. That’s more work than just a plain switch and how much work depends on the specifics of the individual button, so it’s not unusual to see those get left out.
As far as the specific thermostat you mentioned, they might just not have gotten around to it, it might be using different clusters than the one that does work, there might be some other technical reason.
But you’re going to run into this on pretty much every platform that is providing a matter bridge. They will bring in some features from some devices, but as to which ones, you just have to research the individual models. 
And as you noted, there’s nothing smartthings can do about it. You have to make your request of the company that manufactures the matter bridge, since they’re the only ones that can change which nonMatter devices get imported through it.
2 Likes