There is some speculation on who wins what percentage of hands in online blackjack. Some think that there is a difference in online blackjack to the point that it impacts the percentage of who wins hands in the game.
While there are some differences in online blackjack and blackjack played in a brick and mortar casino—such as card counting, which cannot be used in online blackjack—there are some things that do not change. The house edge is one such thing that does not change.
While players can still use basic strategy in online blackjack, there are not enough differences to impact winning. The house is still going to win roughly 48% of the hands that are dealt while the player is still only going to win 44% of the time.
The reason for this is still found in the basic structure of blackjack. For one thing the player still plays first. For another the dealer does not put up any wager to play a round.
On the other hand the dealer is not allowed to double down or split pairs. Those plays do give players an advantage but they need to take advantage of them when the opportunities come along. To help guide players there is basic strategy.
Basic strategy tells players when the most opportune moments are to double down and split pairs. This allows players to make the most of these hands which contributes to increasing their odds on winning those 44% of hands. If you are only going to win 44% of the time you want to make the most money off of them and that is where knowing when to double down and split pairs since players can win more money off of those hands than on a standard hand.