Wall tiles are not suitable for use as floor tiles, though floor tiles can be used as wall tiles if desired. This is primarily due to weaker materials being used in wall tiles than in floor tiles.
In addition to using weaker materials to produce wall tiles, wall tiles also have a weaker glaze. This results in much quicker wear on the wall tile finish if it is placed onto the floor. Wall tiles are also not designed to take the impacts common to floor tiles. As such, a wall tile is more likely than floor tiles to suffer from spalling, chipping or cracking from regular floor use.