Thats a really cool tool they have there! The router "knows" where it is relative to optical (im guessing) locations and compensates for human movement as it cuts along the predefined path. Its pretty ingenius. The only drawback I see is its strictly 2D at the moment.
It is really cool, but to me it doesn't seem practical. You're right about the 2D movement, hadn't really considered that.
By chance did any NCWW member order one? It will be interesting to see it's use. It isn't cheap, that's for sure.