Scorched air is the worst type of heating next to under slab systems.
Lets keep it simple.
Anything that is a good conductor of electricity is a good conductor of heat.
Air BAD for currant flow Water good HUH?
Putting piping under “cement” BAD for electric flow BAD for heat huh?
Cast Iron holds the heat for hours and hours a good thing
Air cools fast BAD THING huh?
Drafty hot spots are annoying Dusty and filters are BAD water no maintenance huh?
Which do you think is better?