The debit card mailed by the Bank of Communications credit card at the same time is for your convenience to bind the credit card for automatic repayment. It doesn't matter if you don't open the card, it doesn't matter. The annual fee of Bank of Communications debit card is 1 yuan, and the average daily deposit of debit card is lower than that of 5 yuan, which is 3 yuan per quarter. However, it is recommended to open a card, so that the settlement account of Bank of Communications can be opened, and it is very convenient to transfer and remit money. If the deposit is higher than that in 5 yuan, the maximum annual fee in 1 yuan will be charged. In addition, it is bound to automatic repayment by credit card. In case of no repayment, Bank of Communications will charge interest according to the balance, instead of charging interest in full.