What a great way for the Mob to launder some money.
Just place a large amount of cash in the winnings and send Guido over to play his luck on the no payout machine.
The mob ran anything with a slot in it. Pinball machines, jukeboxes, washeterias...
You can click credits and launder the "quarters". That's why such machines are regulated by the State.
Additionally, theaters showing Deep Throat didn't sell tickets in the box office (for that film). A guy stood there with a clicker. Who knows how much money may have been laundered clicking "dollars" in the till.