Coincidentally, have been sleeping on the floor (carpeted floor & on a yoga mat, mind you) for a week now and it has been a surprisingly pleasant experience tbh. I literally only had 1 night where I woke up more than once, but also a small caveat, I was jetlagged when I first started this so that probably made the transition easier for me. 

Anyways, overall I haven't felt huge differences to my physical well-being (although I feel like it might be helping me recover from workouts quicker - but this might be a placebo effect) and my overall need for sleep has been declining for a while now anyways, so I also can't really comment on the validity of that point that much.

But since I have no bed nor a mattress ATM and for now, haven't experienced any downsides to sleeping on the floor, I'll continue doing so for the foreseeable future.