BoatyBall doesn't own any balls: they manage reservations for the ball owners, who are the same people who own the fcfs balls.

The owner sends out an attendant to collect the fees in cash, has to track that cash and take it to a bank - on another island - and wait in line for over an hour to deposit it. Or it shows up in his bank account.

The mooring owners choose to associate with BB, and they are in the best position to choose the system that maximizes their financial success.