I love the look of a painted hardwood floor. Especially when it is a light color...say white or pale gray. It is a perfect solution for floors that are in bad conditon and would need some major refinishing. But lately, I have seen it in rooms where this does not seem to be the case. There are so many options for color and pattern that it has nothing to do with hiding anything, it is about enhancing a room. In some cases it is the focal point! Here are a couple of my favorites from Pinterest:
I also love the concept of a painted concrete floor. That is something I could do in my garage/studio!