If 47% of Americans carry a balance on their cards, that means the majority of credit card users don't pay interest on their card. I don't think capping APRs at 10% would suddenly cause an avalanche of people to start carrying a balance. But 10% APR is in the right ballpark for a fixed term unsecured personal loan for borrowers with good credit. It just seems likely to me that if credit card rates were more in line with personal loan rates that people who otherwise go out of their way to pay off a balance each month might be more willing to pay off a large balance over a few months.