1. When using a credit card abroad, you don't need to enter a password. Only the cardholder's signature can be used, so signing at the back can ensure the safe use of the credit card.

2. Once the credit card is stolen, it is possible to reduce the risk of credit card theft by checking the signature.

3. Withdraw money or deposit money at the ATM. In the case of swallowing the card, the signature on the back of the credit card can easily verify the identity of the cardholder.