Pedal-assist feels to me like a complete red herring to the actual issues. It's often an arbitrary line but it doesn't make much difference to safety at all. (nor, IMO, do power limits, because it either limits cargo bikes or makes lighter bikes a lot less predictable: I would think an acceleration limit would be a more sensible option).

(build-in speed limits that are significantly below what the average cyclist can achieve by pedaling also seem kind of silly. IMO people might not bypass such limits as much if the limit was put at a more sensible level)