Thermostatic radiator valves basically adjust the temperature of each individual radiator (and also the room) separately. The old style of putting a thermostat in the one area you don’t live in (the hall) obviously wasn’t very practical. So a thermostat in each room regulating each individual radiator makes a lot of sense. You can have the rooms you are in most, warm while you might want your bedrooms a little cooler.
This makes Thermostatic radiator valves very economical. You save money & your home is much more comfortable at the same time.