I could totally imagine moving my head a little bit as i walked through and banging it on the slats. Who needs a door that only opens that tiny little bit, anyway? It's not like it would keep anyone out more than a door that opened all the way. Granted, it would be fun to show off to friends.
On their website, they have a picture of a garage door version, now that would be cool!
EDIT: I just watched the video they have demoing it. It isn't nearly fast enough, and the shape of the opening isn't nearly as form-fitting as the picture indicates.