I use one, only when tent camping.
It gets low in the middle of the night due to lowering ambient temps.
It acts like a big heat sink and sucks the heat out of my body.
You can buy a quality mattress for your RV. I'd go that route long before considering an air mattress.
Air mattress is fine for short term, like tent camping or in the back of my truck canopy, or the floor of my cargo trailer, but I'd never consider one as a permanent (or semi-permanent) solution to replacing the mattress in an RV.