Actually I think @simplicio might have hit the nail on the head. If you want to take out a line of credit from a bank, you have to be physically present at the bank to do so.
It would inconvenience SOME who don't live near a bank and shopping loan offers around will be harder than going on Quicken Loans, but it would also make it nearly impossible for the giant crime-rings that outside of the US to steal identities and open up credit cards.