This is a bit out of touch with reality, presumably you don't have a car and seemingly are against any normal sized cars or bigger. A very narrow use case should change the world we all live in?

Tiny cars can't do longer distances (aka higher speeds) safely, physics of car collisions won't let you. They have been around for quite some time and popularity is as it is. If you are hit by 50kmh car as a cyclist (seems like frustration/fear of yours thats behind your words), whether car weights 600kg or 1300kg doesn't make much difference to your resulting state. Personal cars have specced brakes according to their weight so breaking distance is cca same regardless of weight.

Where I live (also went through kids birthday party today back & forth few times) - somebody with ebike would freeze their ass in windchill of fast moving bicycle would be below -10C (situation 5 months of a year), slip on partially frozen road could be fatal, moving around on rather narrow roads that have very little room for anybody but cars (Switzerland here but no high altitude) would be literal playing russian roulette with rest of traffic, triple that with wide cargo ebike. Alas, all parents came to the party in forest hut just above our village in their ICE or hybrid cars.