If you swipe your card overseas, if you don't take the UnionPay channel, the bill will be calculated in US dollars or euros (depending on whether the dual-currency card you open is US dollars or euros). You can pay in USD/EUR directly at the counter. However, domestic banks have various restrictions on accepting foreign currency, such as US dollars, and some denominations are not accepted in some years. Therefore, it will be more convenient to choose to automatically convert US dollar bills into RMB bills. Just return the RMB directly in this way.