It's a good concept for some circumstances, like for riding in places without steep hills; however, there's several disadvantages. You're permanently limited to the motor's torque (70 Nm), so on a hill, standing on the pedals will only charge the battery faster. The motor will still slow down and stall out on anything above 15%. Secondly, there's a weight penalty. Thirdly, the efficiency loss of your pedal effort must be something like 25% compared with 5% for a chain drive. That's not a problem as long as your battery has some charge in it. lastly, it's 650w, so not legal as a pedelec.
It's a great idea with some potential, which, no doubt, will gradually be improved on, but I don't see it being any use to me at the moment.