Contrary to the common perception of users paying off balances monthly ("transactors"), the majority—about 60%—are "revolvers" who carry debt. This group is the primary source of profit for card issuers, as they are subject to interest rates now averaging a staggering 23%.

The same banks issuing high-interest credit cards offer substantially cheaper personal lines of credit to customers with identical FICO scores. Despite being a logical tool for consolidating expensive card debt, these products receive almost no marketing, making them largely invisible to consumers.

Senator Warren highlights a critical omission in standard economic calculations: the cost of servicing debt. Expenses like credit card interest and student loan payments are often left out, meaning official data doesn't capture the full financial pressure American families are facing.

The massive 100x return on investment for card issuers like Amex and Chase makes them insensitive to the card's cost. This dynamic protects Composecure's high margins and discourages issuers from switching to cheaper, lower-quality suppliers for their most valuable customers.

Affirm offers a physical card that switches between debit and pre-approved credit. Instead of mass-advertising it, Affirm offers it exclusively to its existing, trusted user base. This deepens the relationship and drives retention without the high marketing spend of traditional cards.

While many assume high credit card rates cover default risk, actual charge-offs on revolving balances average only 5.75%. This is a significant cost but accounts for less than a third of the typical interest rate spread, indicating that other factors like risk premiums and operating costs are major drivers.

By engineering your model so that the gross profit from a new customer in their first 30 days exceeds your acquisition cost (CAC), you can fund marketing on an interest-free credit card. The customer's own payment repays the debt before interest accrues, creating a self-funding growth loop.

Consumers are largely insensitive to the interest rates they are charged, rarely seeking out cheaper options like credit union cards. This behavioral pattern means that cutting rates is an ineffective customer acquisition strategy. Instead, issuers invest heavily in marketing, which proves more effective at attracting new borrowers.

Affirm's CEO argues the core flaw of credit cards is not high APRs, but a business model that profits from consumer mistakes. Lenders are incentivized by compounding interest and late fees, meaning they benefit when customers take longer to pay and stumble.