Can someone explain to me why S17 is the better of the two? There are two scenarios where this comes in to play dealer A up 6 below, 6 up A below. With the first the player will do his best to make 17 or better with his hand. With 6 up the player will stop with anything greater than 11, leaving the player to lose with 12-16. In my mind I would think it would be in the players best interest for the dealer draw. Can someone give me the math on this? Just seems with A up your already making your best attempt and 6 up there are several losses coming with standing on 12-16.
I think you just have to trust the math on this one. It's a 0.2% increase in the house edge so pretty minimal impact. I've definitely had hands where the dealer hitting the soft 17 caused them to eventually bust making my stiff hand a winner but out of millions of hands that will happen less frequently I guess.
I think you just need to look at it from the perspective of the dealer's hand. Understand a soft 17 can happen in other ways also - i.e. 2,4,A after 3 cards. I think the math simply is that the dealer hitting a soft 17 will end up with a hand better than 17 more often than they bust. On the first card 4 out of 13 cards help the dealer's hand - 4 more give the dealer a hard 17 so are a wash. The other 5 options will have the dealer take another card - which could result in a bust but may also result in an 18-21. Again, without going through all the math the point is that the dealer will make a hand slightly more often than they bust.
As a player you always hit (or double) with a S17 so it makes sense that it would be better for the dealer too.
Think about it this way: If you knew, in advance, that the dealer would get a hard-17 every hand, and your hands would continue to be random, as usual, how much would you bet per hand? Hopefully, your answer is "the table and/or casino maximum bet". 17 is a terrible hand...terrible for players and terrible for dealers. Dealer or player - you will lose far more often than winning with a 17. Math is clear - you would never hit a hard-17, as the odds of a single-hit bust are huge (9/13 vs 4/13). Soft-17? You cannot bust on a single hit, You improve with 4 out of 13, and stay the same with 4 of 13... (8/13 vs 5/13). Bottom line? If the dealer has 17 and must stand, you will win 3 of 5 times. That's 3 of 5 for hard-17s...and 3 of 5 for soft-17s. Letting him hit the soft-17s gives him a risk-free (no-bust) opportunity to improve his hand 4 out of 9 attempts (A-2-3-4 vs 5-6-7-8-9).