joists and floor boards might have been considered. We have rough cut lumber. Very rough and a dust magnet! Sure, you could slather on the high gloss, super thick white paint, but unless its a look your going for, it will be rough and dusty.
Also, if your in a newer home you may not have plank floor boards
keeping the floor boards in place and you could take the time to grind all the ends off them but you'll still see every last one of them. ( I don't even know whether anything will happen if you cut the nails, like floor boards popping up or anything, but I'd check )
In the end, I decided just to do a paneled
add some wooden beams over the paneling (bead board) and fake it.