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%.

Despite the rise of mobile payments, even digital-first companies like Coinbase and Robinhood are launching premium metal cards. This trend validates the physical card's enduring status as a powerful tool for acquiring high-value customers, countering the narrative of immediate digital disintermediation.

To enable agentic e-commerce while mitigating risk, major card networks are exploring how to issue credit cards directly to AI agents. These cards would have built-in limitations, such as spending caps (e.g., $200), allowing agents to execute purchases autonomously within safe financial guardrails.

A surprisingly large portion of high credit card APRs covers operating expenses, particularly marketing. Issuers like Amex and Capital One spend billions annually on customer acquisition. This spending is passed directly to consumers, as higher marketing budgets correlate with higher chargeable rates.

The 1929 crash's roots aren't just in stock speculation but in a 1919 cultural shift where General Motors began offering car loans. This normalized consumer credit, which was then applied to appliances and ultimately, stocks on margin, creating the bubble.

The chargeback system creates a powerful perception that using credit cards is virtually riskless for consumers. This sense of security, intentionally cultivated by the card industry, was critical for overcoming early internet fears and unlocking billions of dollars in online commerce that would not have otherwise happened.

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.

The system of charging retailers an interchange fee (around 1.8%) that is then passed to consumers as rewards (around 1.57%) creates a strong network effect. Consumers are incentivized to use rewards cards, and retailers cannot easily offer discounts for other payment methods, locking both parties into the ecosystem.