i think i looked up stats once. most of the accidents which are with vehicles are too bad for helmet to matter. I want to say helmet may help with 20% of all bike accidents. electric bikes, however, are a different story... they require a level of safety and caution above traditional bikes. please use helmet
yeah, they never have good enough brakes, and the motors are always under powered, and they really need to have both regen and disc in all cases on both wheels, should be minimum 500W, and the brakes should have 1/4" thick discs and hydraulic mechanical actuators