The best thing about this whole “experiment” with ST is that it allows you to gather data to make that sort of conclusion, since everybody’s house is different and everyone’s preference is different.
In my case I have a two zone system, with radiators downstairs and hot water baseboards upstairs. I’ve been logging temperatures for a while and I find that if you go down really low on really cold days, it will take the system a couple of hours to bring the house to a comfortable level. Now depending on prices and your expectations, and your own heating setup, that might be worthwhile, or it might not.
If you know your fuel consumption, oil prices and how long your furnace / AC has to run to keep your house comfortable then you can decide on your own whether it’s efficient to keep it running through the day, to lower it a few degrees or to drop it all the way to the floor.
One of the other advantages of this whole “connected” business is that you can decide on the fly, or even be proactive about it. If you know tomorrow it’s gonna be 5° outside all day, you might decide to run a different schedule that keeps the thermostat at 70° so the house never gets too cold. Or if it’s going to be 45° instead then you can drop it down to 60° while the house is empty and fire everything up a couple of hours before people arrive.