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I've worked on a property that has heated ceilings........ Its a fucking nightmare.
Even though as @hoefla says its a low temp radiant heatsource the temperature still rises enough to cause the ceiling structure to expand which leads to inevitable shrinkage and cracking of plaster. My client had to replace the plasterboard and plaster in the ceiling twice before disabling it and putting 'normal' heating in.
I was never there when it was on so could not comment on how efficient it was.
EDIT - the building was a 1980s build so it is possible that the kinks have been sorted out since then but the fact that it has not become more widely adopted makes me sceptical about that.
I (as a renter of an old apartment in Berlin with a gas boiler from 1986) have been thinking about heatpump stuff a lot, just because it seems to be a main point regarding CO2.
My latest fictional plan is heated ceilings