If a smart thermostat is turning on at a factory set "default time", I wouldn't consider it to be doing its job of adjusting the timings based on your usage habits.
I don't know how the smart thermostat is supposed to know your behaviour unless you tell it, which means taking it off the default. I had to tell my thermostat explicitly when I wake up.
With room occupancy detection, it should start modeling likely HVAC needs - able to predict accordingly, and adjust power use & timing jitter accordingly.
Ah, that's another level of smart than I was thinking of and requires integrating motion sensors, but I do suppose that would enable it.