tldr: not worth it
I've been a minimalist for several years now, so when a few months ago after a sleepover at a friends house I had already slept on the flor for two days, I decided to extend the experiment.
Sleeping in a sleeping bag got better up until day 4 or 5 where comfort plateaued. I then had 2 weeks of back and fourth between bed and floor before giving up my first real attempt.
I then tried again recently, but it's still not very restful. I can sleep and I'm functioning well the next morning, but the whole night feels shallow, like it's just an extended nap. The 6mm yoga mat wasn't thick enough to prevent sore spots after some time and it wasn't wide enough to make sure my hands would never slide of if I wanted to place them to my side.
During both attempts I used my slippers as lumbar support which worked pretty well. I slept on my back. I also tried some side positions, which work but are inferior and only really viable if you need to move a bit to get to sleep.
It wasn't all bad though, getting out of bed was easier and it saves space. You also give your body a workout while you sleep and will inevitably do 30+ minutes of various stretchy positions before you give laying still your first shot.
Maybe with a thicker yoga mat and some more tactical coushins I can remedy the disadvantages, but for the time being the floor can have it's 2:0 win.