I think in real life there are more constraints. For example there are people that sleep better at a lower temperature than the daily one (so leaving the thermostat at the same temperature it's a minus for them).

Regarding "what is better" from energy efficiency, I would prefer a system that "check it" because my guess is that it depends a lot based on the individual situation. I mean everybody is going crazy over "IA" but a couple of sensors and a system smart enough to adjust your usage based on your particular situation and preferences (like "eco", etc.) is an exception.