These days lots of those machines take paper money, and some even take credit cards. A couple of years ago, I bought a newspaper at the DFW airport on my AX card. I think it's the last newspaper I've bought for cash or credit.
BTW, the current cash readers are substantially different than they were 10 years ago. When our money was changed to include metal threads in the weave of the cloth it became, for all practical purposes, the same sort of thing as our coinage. The older image scan systems disappeared and more reliable, cheaper and easier to fix electroconductive systems replaced them.