yup USAA either wants a full banking relationship or relationship at all
I don't think so.
I have never had any banking relationship with them. In fact, up until a couple of years ago I never even knew they had branched into banking. Without having any banking products and without having had insurance through them for at least the past 5 years, all of a sudden I get an e-mail from them saying that my pre-approved USAA AmEx offer will expire in 2 more weeks.
I'm fairly certain they look at many things such as curreent military status, pay grade and duty assignment in addition to credit scores.