If they are about 2ft square and 1/2 inch thick, I have them on the concrete floor of my woodshop. They work well and are pretty rugged.
The draw back is that they hold water underneath. Inside on a concrete floor this is not a good thing. But on a deck or stone floor, they may be okay.
I would be concerned about bacteria growing in the pores of the pad. I have shoes on in my shop but barefoot around the tub might be a problem.
Watch out for that chubby green guy under your toe nail.