Comment by insane_dreamer

because poor people, typically: - do not quality for high-rewards cards (which have higher credit score thresholds) - if not savvy, carry a balance because they can't afford to pay off the amount in full, are subject to higher interest rates because those are the cards they qualify for, and thereby pay much more than than well off consumers (increasing the transfer of wealth) - if savvy, realize that having a credit card costs them more than not, and stick to cash - are more likely to be receiving payment for services in cash themselves and will just spend that rather than depositing and using a CC (if they even have a bank account)

(update: 4.5% of US households are unbanked; these are mostly from the lower quantile) https://www.fdic.gov/analysis/household-survey/index.html