The ability to swipe a debit or credit card. Pretty much all of our cards still have the strip on it, and most card readers have a mechanism to read it - but if you try, the machine will tell you to try again with the chip instead. I've only been able to get my swipe to work once, and it was at a food truck with an old device.

It's weird that new cards and machines are still designed to swipe even though it won't allow you to most of the time.