Comment by maz-

Not sure if you've heard of the Sur Ron or the Cake bikes but they're RAPID. I have a modified Sur Ron and it's way closer in performance terms to my Husky 701 than an e-mtb or similar (peak power to weight ratio of about 0.3hp/kg).

People put pedal kits on them to try and hide the fact it's basically a super light motorbike but in my experience it's not really suitable for riding on bike paths or trails.

Devices like in the OP are much more of a grey area as it's basically impossible to tell their power output / weight on an individual basis...