Smart TRVs

I was thinking to myself recently about these and I realised, they’re right on the floor (in most cases). Where as things like thermostats or temp sensors are usually placed about 1.5m or higher above the ground. Whenever I get down in the floor with my 4 year old I notice the difference in temperature from “adult world”. So surely, at least some of the savings you get from these smart valves are mitigated by the fact it’s keeping the radiator on longer to get the lowest level of the room to the set temperature. And surely that also means that up at adult height, the temp must be higher than what you set the valve to?

Anyone care to weigh in? Am I being stupid somehow?