A debit card allows you to automatically repay your balance after applying for a credit card.

However, if your debit card has no source of income, you still need to transfer money from other bank cards to the debit card. In that case, the Bank of Communications debit card is meaningless, because with other bank cards, you can directly transfer the money to the Bank of Communications credit card for repayment, or you can take cash directly to the Bank of Communications to exchange for credit cards.

Having too many cards is not necessarily a good thing, because you may also be charged an annual fee. There are also passwords, etc. If you lose them, it will be very troublesome.