Splitting is a sometimes tricky play in blackjack. Many players do not execute it at the right times, but that can be reversed with practice and by applying strategy. But perhaps the trickiest to logic out is splitting Aces.
When dealt a pair of Aces, you have the choice of playing it as a 22, which is just silly, or of playing it as a 12, making it a stiff hand. Or you can split the pair of Aces and wind up with two individual hands each starting with 11. This is a much stronger way of starting a hand than with a 12.
The only downside to splitting a pair of Aces is that most casinos will only allow a player to receive one card on each Ace once they are split. The same rule often applies in online blackjack games as well. That is how good the odds are on split Aces