I drive a CB250 17 miles to work. It gets 70+ mpg. It seems to be fairly economical. I have an Elio reserved. It will get similar or better mpg and I won’t have to wear a rain suit in bad weather.
Even if you are very careful motorcycles have a terrible safety record (and mile for mile bicycles are probably worse). Many drivers fail to see them and there is little protection in an accident. The cost of one hospital visit will negate any savings. Traveling in a 4 wheel car is so significantly safer it can't be ignored.
In poor countries, scooters are the norm. The people are all banged up and scarred from scooter accidents.