Floppy disks are still used in industrial automation. If something works, you don't mess with it until you need to. The thing with floppies, is that there are lots of them floating around, and they last a long time. You can also write different information to them.
I've got a couple of 8" floppies near my desk that aren't used for anything anymore, but I bet they still work. So even though there are no floppies being produced, the existing supply of floppies will last a heck of a long time.
I don't think the North Korean soldiers have much choice.
If I were a DPRK soldier sent to Russia, I would be taking notes on how to desert, although Russia and North Korea probably have a decent amount of experience dealing with this, so chances might be slim. Still, I'm thinking the chances look better.