You can save money, but there is no interest. There is a handling fee and interest when withdrawing money. Some banks also charge management fees for overflow deposits. Therefore, if you have money, don't deposit it on a credit card. Not cost-effective (credit card spending is good), especially when money is urgently needed, it is not cost-effective to withdraw cash. It's better to have a savings card with a little interest, as well as balance treasure and income.