I don't get it- it propels the bike so slowly on its own, and if you were to use it as supplemental power, you'd be turning the flywheel too, slowing you down. Seems there's a clutch or differential missing in there somewhere.

I guess it's a start, but right now it's little more than a novelty.

Not to mention, I'm not exactly pumped at the thought of both the weight of a flywheel and all that weight moving that close to my future descendants. Maybe I'm alone on this, but I occasionally sit on the top tube while in motion to reposition and relax.