Split instead, and you win close to 50 percent of the time. You'll still lose money overall, but not nearly as much as if you stood. This is a classic situation where the goal is not to win but to lose less. That would be an even proposition if the dealer had blackjack one-third of the time he started with an Ace. But he doesn't, because only 30.8 percent of the cards are 10-values.
Basic strategy is a closer call on some hands than on others.
Card counters track many hands in which the balance of high and low cards may change the way they play. But even for an average player who pays attention only to his own cards, there are a couple of hands where small gains can be made by basing your decisions on not just the total value of your cards but also the individual cards themselves. Now you've taken two cards out of the deck that could really help you. A 4 would give you 20, and you've already used two of them. That's enough to make the difference, even in a six-deck game.