Split & Double Down

Hello,

the 'Wizard of Odds' is simply awesome!!

The question I am struggling with is whether split in Blackjack is in the player's advantage or in house's advantages. While I understand why double down creates an advantage for the player, I've had an argument with my friend that split is simply innitiating an extra hand thus does not held any advantage for the player.
Anyone can answer this? Wizard? I tried the calculator on the W of O site but it does not have a feature for no split allowed.

Thank you

You don't just "initiate an extra hand". You replace your current hand with two different hands, that have a better combined expectation than your initial hand.
For example, if you have two eights, your hand totally sucks, splitting it into two eight-point hands gives you two chances to do better than 16.

Disallowing splits raises house edge by about 0.58%, compared to max. 4 hands splits (S17, DAS, infinite deck).

It's interesting to take a look at these tables, which shows you the value of hitting vs splitting with various hands.

Some splits, like 8,8, you are just turning a terrible hand into two less terrible hands, like weaselman said. Other splits, like all A,A turn an ok hand into two good hands. Finally, some splits like 9,9 against a 6, turn a good hand into two less good hands that together are worth more than the first hand.

Oy. Every time you split according to BS, you are doing better than not splitting. But sometimes you are expected to win, sometimes expected to lose.