Someone paying for lunch with a stablecoin card doesn't need the restaurant to know what $USDC is. The card works like any other at the terminal, with the customer's digital dollar balance funding the purchase while the merchant receives regular dollars through its usual payment provider.
That leaves several companies to collect fees for connecting the two.
Visa enables this arrangement through its partnership with Bridge, which allows customers in Colombia to spend stablecoins while merchants receive Colombian pesos.