[matthewdgreen]

The problem is that the credit card "lending money" function is not what transaction fees pay for, and these fees are paid by all market participants -- including cash customers. People should be able to separate the payment function of a credit card (which is what merchants pay transaction fees for) from the "line of credit" function that banks make money on. However, this scenario would be less profitable for the industry, and so a small cartel of payment card networks and operators have worked hard to jam the two functions together. As a result, everyone (including cash customers) is heavily penalized for merely participating in the economy, unless they also purchase a profitable and risky line of credit.

It's frankly a brilliant scam, and the fact that people don't think it's a scam is its most brilliant aspect.