Did a bit of digging so you don't have to: It's got 8Wh of supercapacitors, and presumably does a reasonably efficient job of regen. So it's enough to help you up a moderate hill, but on average you have to do most of the work yourself. (It's obviously not the perpetual motion machine the headline suggests.)
I can see a real future for this approach if it can be made lightweight and unobtrusive: Just the thing for leisure cyclists who aren't as strong as they used to be.
But it's not a replacement for traditional battery powered workhorse e-bikes.
