Isn't this the same if you have a 'dumb' thermostat set on a schedule, which is presumably what most people have anyways? Even if you have a 'really dumb' thermostat, presumably people are waking up at similar times and turning on their heaters...

I sometimes wonder if the smartest thermostat isn't actually a 'really dumb' thermostat on a timer. As in, you want it to be warm? You have to get up and set the heater to 21C/70F, this turns off after 4 hours (or when you lower it). This way if someone hit snooze, their 'smart' thermostat isn't turning on the heater at 6AM. If they usually are home at 7PM but have dinner at a neighbors house, it doesn't think they are commuting home and start turning on the AC...