Charles Payne warns of a collapse in American spending, citing steep declines in restaurant, airline, and lodging purchases. Bank of America data shows credit card spending stagnating as debt hits record highs. Rising interest rates are squeezing consumers.
Nothing except your entire purchasing history which can be used to infer all sorts of things about you.
As well as the 2-4% that the merchant pays to them for every one of your purchases. That is passed on to you in the price that the store charges. Only gas stations regularly give you a discount for cash, and that discount is them just removing that 2-4% up-charge that they need to include to cover their payment to Mastercard or Visa on the very thin margin that they make in selling gas.