I have no experience of US credit cards for Asiana, though I understand there are dedicated cards which earn Asiana club miles. In the UK there is the Amex SPG card which earns SPG points 1 point to £1, that can then be transferred to Asiana miles. This offers an advantage in that the SPG points don't expire while you credit to the scheme regularly. I believe Amex also offer a SPG card (possibly with signup bonus) in the US. It is a shame they are not offered in more countries serviced by Amex e.g. Australia as SPG is a useful scheme to store points in as you can transfer to more than one airline as well as redeem SPG rewards.