So you got a smart thermostat, wrote some code to hit an API, and do some fancy math to half your heating bill.

Why could you not just turn your thermostat down 4 degrees for the same thing?

I get that there might be some marginal gains you can get with tech ("A heat wave is coming tomorrow, let's shut off the furnace 1 hour early"), but it seems really small and crude compared to existing offline tech can do (look for leaky holes in your insulation, add 6" more blown insulation in your attic, etc"). Or for example replacing a 80% efficient with a 99% efficient furnace has a pretty huge impact. Does nest magic timing have more?