Credit cards are very profitable. Like many banks that promote credit cards, their profits account for 30%-40% of the total profits, don't you think? The main profit of credit card comes from interest, such as credit card installment, interest on the minimum repayment amount of credit card, annual fee, etc. Also, the credit card limit has no cost, but it has nothing to do with bank deposits. So the profit is very big, that's the reason.