Why?

To meet the needs of people in post WWII Europe, of course.

Cheap.

Simple to manufacture.

Simple and cheap to keep running. (At the time)

Plus all the performance you could ever need.

This model has:

14hp

78 mpg

0-60 mph in.....probably never. Maybe on a steep hill.

0-53 mph eventually. I'd personally not drive it over 35-40.

Seats two. Supposedly. More like one and 3/4 people.