Yeah, I don’t blame you not wanting to commit to a hub if you’d only have this thermostat.
Depending on what features you want maybe you could find an offline one with those features built in. I know there’s ones with schedules and presence detection that are fully offline.
Absolutely, if full local control is what you want and you expect to get more devices then it’s worth either reusing an old computer for home assistant or getting a home assistant yellow.