Well, in the US, credit card debt is normally a loan of goods or services, when it's not a cash advance. So it's consumer credit. I'm not sure what the definition is wherever you live.
Regardless, loaning Bitcoins isn't required for such services; and they can support a Bitcoin bank perfectly well.
Ok, you can continue making up your own definitions. According to
http://en.wikipedia.org/wiki/Loan credit card debt is an unsecured loan, which i already pointed out. This will be my last post regarding this subject, i'm not here to argue about definitions.
If you can show me a way how a bitcoin bank can pay
1. interest to its depositors or
2. earn money by lending
i will be happy to continue with the discussion.
alexk