Because it's directly returned to your credit card.

After the credit card is refunded, the money will be automatically deposited in the card. In fact, the refunded account did not really enter the credit card, but became an overpayment of the credit card. If it is a refund that arrives before the bill date, the consumption can be deducted, but if it arrives after the bill date, the repayment of the current month cannot be deducted and can only be included in the bill of next month.