Guessing here ... But in the old days when everyone got a real paycheck (not direct deposit), some of the casinos would have promotions to stop by the cashier's cage to cash your paycheck. They had a Wheel of Fortune with various prizes, from a free drink or free spin on a special slot machine, up to (in this case?) triple your paycheck.

They figured you would spend / gamble at least some of your paycheck after the cash was burning a whole in your pocket!