I would suggest that your progression theory omits a significant step:-
i.e.: "Central heating with multiple zones and multiple thermostats and standards TRV's"
e.g.
For more years than I can remember our heating system in our relatively modest 4bed 2bathroom home,
has had a 4zone heating system. with a traditional 4zone, 24hour, 7day, digital time clock programmer.
So, we have;
Downstairs radiators zone with its own thermostat + rads with TRV's.
Upstairs radiators zone with its own thermostat + rads with TRV's.
Hot water cylinder zone with cylinder thermostats.
Towel radiators zone + rad in utility area with its own thermostat including pipe stat but no TRV's.
The property was originally a more basic 2up 2down, no garage, but sufficient land to extend to the side & rear..
We have extended the property twice over the 30+ years we have lived here.. (adding bedrooms, bathrooms, garage, kitchen extension etc)
Including banging in loads of added insulation, (loft voids, void under floors), as and when alterations have been in progress.
The result is that even if we came back to a cold house, just sticking on the downstairs rads, soon warms up the main living areas..
Reality is that downstairs heating is on earlier than the upstairs heating.. (and some downstairs heat will drift upstairs due to heat rising).
Individual TRV's will turn rooms off if they get warm enough..
Towel radiators, (plus the bathrooms), are warmed up around the normal morning / evening washing times..
Hot water ticks over around the typical hot water times of most average systems..
If for any reason we needed to boost/adjust any aspect of our heating..
then 99.99% of the time one or more members of the household would be walking past the thermostat and/or program timer so could adjust the temperate or the active time with 1 or 2hour boosts etc, etc.
As normal daily life includes walking to the kitchen, bathroom, other rooms, rubbish bins etc. etc. to continue normal everyday activites.
(we certainly don't just sit down in the lounge all evening after getting back from work!).
And, unless all doors are kept shut, individual smart room thermostats will have some element of heat drifting to or from adjacent areas of the property.
So my case would be:-
A well-designed multi-zone traditional heating system would have negligible benefit from the expense of installing smart valves.
Whereas a basic single heat zone, (whole house) system, could simulate a multi-zone heating system by installing smart TRV's.
And, Holiday lets, Air BnB's, Rental accommodation can benefit from remote phone-app heating control..
But battery failure on any wireless device can be a real pain-in-bum!!!