Point Spreads versus Odds

Why do bookies use the point-spread device for wagering on football games when odds betting on the winner is also feasible? One possibility is that point-spread betting is more fun than odds betting. The existence of point spreads, however, does not logically entail this "more fun" explanation. Given simple specifications of beliefs and betting behavior, and given that point spreads and odds are equally thrilling, it is demonstrated that the point-spread game can exist as the game produced by a profit-maximizing bookie. The disparate beliefs which create the demand for some form of betting market can also explain the particular betting game produced by the bookie.