How does the “smarts” help? All a thermostat needs to call for multistage would be is statistical analysis for heat/cool deltas and resist, which offline thermostats have been doing for a while.

All the “savings” my “smart” thermostat reports is because I have set-backs, which I had with my old model which also supported multistage heat pumps. The thermostat in question is mind-bogglingly stupid when it comes to handling time of use rates.

So, overall, not very impressed. Happily, I can manage it with Homeassistant.