[rossdavidh]

Well, the "Mum & Pop" stores you mention, are far more likely to be at risk from taking out a loan that they end up not being able to pay back on time, and late fees and compounding interest make the total cost of the credit far more than they expected. It seems like the total risk here is visible, whereas the worst-case risk of a conventional APR model is difficult for inexperienced users to perceive.