This product is unlikely to ever replace bicycles. It will always require significantly more skill and practice to ride a skateboard - powered or not.

However, that's an unnecessary measure of success. The board just has to find a big enough customer base to be profitable. There's room in the world for many different kinds of transportation.

As for legality - certainly there are concerns, but unlike the segway, this board is subtle enough to fly under the radar for a while.