I'll cut bread with my chef's knife (amazon shun knockoff) when I want to make less of a mess. One interesting thing I noticed is that when Scott was cutting bread in the video he was cutting a croissant and no crumbs fell.
It will be interesting to see the knife in the hands of real chefs. Two things I'm curious about are whether the ergonomics of the button are good, and whether the ultrasonic action atomizes foods as they're being cut, changing the experience of cooking in some way.