信用卡簽賬 & 提款透支 ???

因為你簽賬去消費其實都有手續費, 只係d費用轉嫁去了間舖頭度, 一般收費1-3%左右, 因為舖頭同銀行行有協議唔可以收使用信用卡的客人請個手續費, 如果收了俾客人投訴除退款外留有機會被停止服務....
但有一些行業的價錢毛利很少, 例如電腦產品, 電子用品, 酒類, 固有一些小舖會轉嫁手續費給客人, 但為了不違反協議, 有好多都會在你以現金付款時給你一個特別的優惠(現金價)~

因為信用咭原意只比你用買消費，唔比你現金，所以現金
除手續費自已比外，重要即時計息。

It is a matter of bank policy.
Cash is better than credit as you can use them anywhere and there's no restrictions, so I guess that's why banks charge more admin fee for cash.
Bank do charge admin fee when you use them at shops/restaurants but the charge are paid by the shops so you need not pay (i.e. if you don't have any outstanding payment).

the different is take out cash or not~