It's cheaper to swipe a credit card,

Because there is an interest-free repayment period.

Also, if the credit card is also a single-currency card (the card number starts with 6), the scope of use in Thailand is the same as that of a savings card.

If the credit card is a multi-currency card (the card number starts with 4 or 5), it is used a little more in Thailand than a savings card.