Sleeping on the floor gets mixed reviews. There are people that can't sleep on the floor and it hurts their back. When a person has a bad back and sleeps on the floor, they will tell you, it makes them feel better.
You don't want to sleep on the floor every night, but actually sleeping on the floor every once in a while can be very good for your back. It can straighten you out a bit as you're sleeping on a hard surface.