When you combine the number of opportunities to make good bets with the fact that baseball is mostly a moneyline betting sports, thanks to its low-scoring games, the odds for the bettor only increase. Betting against spreads is much harder to predict and analyze for value, but choosing a winner is more straightforward, and it’s easier to gain an edge and make solid bets.
But if you have located true value, then multi's can be tremendous value as you multiply the value into each leg. The issue is of course, locating true value. Everyone who adds a leg to a multi does so because they believe they are finding value. Nobody bets odds that don't represent value to them. But key to creating value multi's is in finding true value or else you're only diminishing your chances of success with each under valued leg you add.
ATS equals “against the spread”. The spread is the number oddsmakers use to give people other betting options besides only wins and losses. A spread for a Premier League fixture would be something like .5 or 1.5. One club would need to lose the match by no more than 1 or 2 goals or the other needs to win by 1, 2or more goals. If the final score doesn’t reflect the number set by the oddsmakers, your bet won’t cover the spread and you can’t win your bet.