This is interesting. I'd assume a printer would be an extremely high-value target for espionage.
But, then, espionage is probably a much less popular way of making money than ransomware these days.
Yes! Printer LEDs have been used for espionage (like visual morse code), and firmware has been hacked to store copies, there is a documentary about this somewhere on the web (havent found it yet). Brilliant ideas!
Great article. The obvious follow up question is "why not?", because every other attack vector is just beaten into the ground.