It's not a matter of outrage, it's a matter of momentum.
Every pause in the purchase process slows down the cognitive momentum of the user, which is why adding, say, forced registration before a checkout is a bad idea.
Admittedly, having to select your credit card from a drop-down is only a small speed bump, but why introduce it at all when there's no benefit and a very real downside?
I would argue there is benefit (what cards are accepted) and little downside. Without testing, I would not be prepared to make a definitive statement though.
Every pause in the purchase process slows down the cognitive momentum of the user, which is why adding, say, forced registration before a checkout is a bad idea.
Admittedly, having to select your credit card from a drop-down is only a small speed bump, but why introduce it at all when there's no benefit and a very real downside?