I give my card to the cashier, they swipe it, I then wait for a receipt to print, wait for the cashier to hand me a pen and the receipt, sign the receipt, hand it back to the cashier with the pen. If they're doing it right, they compare the signature to the one on the card, but in most cases I am then done.

versus

I wait for the onscreen prompt, I tap my card, hear a satisfying beep and am done.

It's pretty obvious the difference.