Room thermostats usually operate "digitally." If the room temperature falls below the set value, it switches ON; if the temperature rises above the set value, it switches OFF (apart from a preset/adjustable hysteresis). It is best to set all room thermostats to the MAX value and then adjust the heating control accordingly to achieve the desired temperature. When planning the design of underfloor heating, rooms with higher or lower heat demand can be taken into account. This is not done (only) with the room thermostat.
Regarding the "savings effect":
Basically, every house has a heat demand that depends on many factors. In many families, it is the case that the woman wants a few degrees more than the man or the rest of the family. The result is that "the heating has to/should be turned up."
If I now set my basic heat demand – say a room temperature of 21 °C with the heating – and cover the "extra demand of the woman" with the wood stove, I naturally save heating costs, since without the wood stove, the demand would have to be met by the heating (or a few blankets or a fan heater *facepalm*). How much energy this actually is remains to be seen.
Of course, the heating system is designed for a certain temperature, and usually a later wood stove is not considered in the calculation (unless it has a water jacket). Nevertheless, for example, with a heat pump, I also only have the function PUMP ON or OFF. When ON, the buffer (if available) is heated; when OFF, it is not (keyword short cycling). And if my total demand is somewhat lower (let’s say only 1 K), the heat pump cycles less because less heat is withdrawn from the buffer.
All in all, the wood stove will probably never pay off. It is a gimmick/luxury item, used more by some and less by others. Therefore, it is better not to consider it in heat planning. But on the other hand, one can be pleased afterward if one can "adjust" the heating curve a bit and thus save a few euros in heating costs per year.