I have a big car, and an electric cargo bike, and frankly, the latter covers a lot of my use cases. It weighs a lot for a bike, around 30-40kg, but carries one adult and two children plus some bags.

I can imagine adding 50-100kg to it, making it 4 wheels, fully enclosed lightweight roof, max speed of 20-30 kph and fully electric, and covering a lot of bike use cases, plus weatherproofing. It's not like a lightweight car, it's like an extremely beefy bike.

The thing that would be missing is road infrastructure and laws. The bike works because it can go everywhere, and things I need are within cycling distance. I wouldn't happily "ride" the beefed-up version on a public road with cars though.