I've done a few breakfalls on a wooden floor (usually due to missing the mats, occasionally falling off the skateboard) and the only difference is that it stings a bit when you slap your hand down.
Once the tingling goes away and you can feel your fingers again, it's ok.
I agree that it's good once you've learned the basics to try to roll on a hard floor so you can find your remaining corners, and work on rounding them off
Ruth