I love micro-vehicles of all kinds.
The re-introduction of The Bubble Car would be an awesome thing to see on modern roads. I'm a little disappointed to see it is an electric vehicle, but otherwise am thrilled.
I only wish I lived in a country where micro-vehicles were legal.
It has to do with weight, dimensions, and engine displacement. Regulatory environments (in NA) do not consider them safe (crumple zones, ability to keep up with traffic, etc.)