This should hopefully make perfect sense to you. Successful betting, on any sport, is all about finding value, so you should always look to get the best value that you can. If a moneyline wager offers the best value on a football game, then that's the wager you should be placing. If a point spread seems the best option, then go down that route. There may even be occasions where it's viable to place both wagers on the same game.
The first thing you’ll notice with moneyline odds is that there is either a positive or negative sign in front of the number. What that sign denotes is how much you’ll win betting on each side. If there’s a positive sign next to the odds, that indicates the amount of money you would win if you bet $100. If the odds on a tennis player said +150, that means that for a $100 bet, you would win $150. Now if there is a minus sign in front of the odds, that is the number that you would have to bet in order to win $100. For example, if a football team was -250, that means you’d have to bet $250 to win $100.
If the implied probability says that you have to win a bet 40% of the time to break even, and you think you’re likely to win the bet 45% of the time, then there is value in the bet. Remember, the sportsbook pays you more the less likely something is to happen. This means you’ll be getting paid as if the bet is only going to hit 40% of the time (more money), but the bet actually hits 45% of the time if you are right.
That was all before Charles McNeil, a math teacher from Chicago, invented the concept of the point spread. An avid gambler, McNeil created what he called “wholesaling odds” and started his own bookmaking operation in the 1940s. He started out offering this new style of betting on football, but his business model grew to include basketball. McNeil changed the way sports betting was done, and his legacy lives on today in what we now call the point spread.