What are the disadvantages of opening SMS in banks?

It won't affect. Debit cards have no overdraft function. If there is no money on the card, the SMS fee, annual fee and small management fee cannot be deducted, but they will be deducted together after deposit. Cards with a balance of 0 and no transaction within 18 months will be converted into sleep accounts and automatically cancelled after about 5 years. So you don't have to worry about your credit status being affected by the insufficient balance of the savings card.