If it's in good shape you can tile over it, add other flooring. You just have to consider adding more height. You can paint with the specialty paint kits sold at Home Depot. Just have to be careful with it, once scratched it could peel.
Cover with what? Floor or wall? You can paint it with Rustoleum or Homax tub and tile paint kits. You can tile over small format floor tile with large format tile. Can't tile over wall tile. The added thickness and weight can tear off the wall.
Have ugly pink tile in old guest bathroom. Can this be removed and prepped for wallpaper. This tile is not in the shower.