Eli5: When your credit card doesn’t read at a credit card machine, why does covering it with a plastic bag suddenly make it work?

Question

Had this done multiple time at the register. Card not reading, so the cashier will cover the ribbon or the chip with a plastic bag and YATZEE, it goes through. Why?

In: 407

Answer 1

Why do Americans still swipe cards? Why aren’t you all contactless? Aren’t your phone wallets contactless, so why aren’t your cards too?

Edit: why aren’t you all using phone wallet transactions? Why are you still using the card?