They look a bit more like bank tellers in Tokyo. It's your local neighborhood T U C shop. In fact, I don't believe it is illegal under Japanese law. They are an independent company which just happens to buy the little doohickys the pachinko parlor gives you in exchange for all those ball bearings, and then sell the doohickeys back to the pachinko parlor for a bit less.

Many Japanese seem to believe these cashiers' profits go straight to North Korea, incidentally.