I did the same as BigJohn. I had the floor of my new garage professionally coated with epoxy and the stuff is wonderful. I have even dropped a jackstand on the floor without any damage. I understand it is critical that there be no oil in the concrete for good results though.
I would worry about spilled fluids getting under an interlocking floor and getting stinky.
Here in Canada back in the day (1950-1960's) service stations used a red garage floor paint, and many of them would repaint the floor every weekend to keep the shops looking spic and span.
I did work for an MG restoration shop back in the 80's with a painted floor, complete with a large MG logo. It looked great. The boss painted it every year. He wasn't into Christmas and would spend the holiday repainting the floor. Ho! Ho! Ho!
