It's a fallback and is still needed in some parts of the world *looks at large parts of the USA*.
It's like the embossed numbers on the front, a lot of large chains will still have a click clack swipe machine somewhere, even if it's not been opened in years.
Something people tend to forget is that banking has a very long technological tail, and depending on where you are in the world different systems are in place, usually trying to retain at least secondary/backup method that might seem pointless.
so your average modern card has something like 4 different ways to read it, NFC, Chip (for chip and pin), magstripe for if the chip fails, and the embossed number for both over the phone use and if a store needs to fall back to an embossing machine.
About 4 years ago the then relatively new Boots Opticians in our town had to resort to the click clack machine because all their payment computers/readers were down, it was the first time i'd seen one used for 15 years or so, they had to get the box out and open it up as it was unused, and the older assistant took the time to demo it to the younger one who'd never seen one.
*the US still has massive numbers of magnetic readers and relatively low uptake of chip and pin, partly I suspect because the banks offload the risk to the customer over there a lot more than they can here.
