In table tennis, footwork is important for all levels.  Using the Newgy Robo-Pong 2050 is one of the best ways to improve footwork.  Most players try to improve their side-to-side footwork, which is important.  However, only a few players try to improve their in-and-out footwork.
 
In-and-out footwork is vitally important for the slow block, especially when you are away from the table.  Watch how Joo Se Hyuk demonstrates the stepping in on this video: