The black market is an inevitable product of economic development.
Especially when two kinds of currency units appeared, it gave a lot of people chances-just like the food stamps and oil tickets in the early years when the country implemented the rationing system.
After all, not all fighters are focused on improving their strength. After many Kung Fu fighters reach a certain age, they find that they are making slow progress, and there is no room for improvement anymore. They have no such desire for those Kung Fu resources, so making money has become their first priority.
So some fighters will use points to exchange money, or they find something good in the Different World, but they don't want to follow the regular process (to pay taxes) ...
Therefore, the black market came into being.
As a city with a space crack, every year, millions of fighters come to Wuen City to enter the different world, so the black market naturally came into being.