This might be the case a few years ago. I just got back from a trip there few weeks ago. All transactions are approved in real time using Point-of-Sale terminals. This was not something available to most merchants there a few years ago. They are everywhere now. So most stores will take any V/MC in Taiwan these days.

However, YOU as a consumer have to be careful. There are instances that a card is swiped twice and gets duplicated for fraud. They particularly like foreign cards as they are harder to trace back. So I will avoid using a foeign card for small transactions, espeically with unknown/individual merchants.

There should be no problem with any major chain department stores.