I switched thermostats due to the old one failing, and getting a basic smart thermostat was required for a hefty rebate that basically made it free… and the one I have now, the app thought my not-major-brand phone was a tablet. I couldn’t hit the button to turn down the heat, only up, because it was cut off due to scaling.

So yeah, requiring apps for interface is bad. Even if you are willing to use it there’s so freakin many various versions of android that it’s guaranteed to not work properly for a whole swath of people, mostly those on budget devices.