It's a worthy question... Technically, it is sort of illegal in a very gray area way... More like frowned upon by the banks... Messing with coins is a felony, since they used to be made of gold... Bills are only a misdemeanor, and not one case has ever been prosecuted... Intent to decirculate must be established, and I never even sign these...
Also, a precedent has been set by the culture around us... When Leonard Nimoy died, millions of Canadians turned their money into Spock dollars, as a tribute farewell... It became such a huge trend that the Canadian government had to issue a press statement requesting its own citizens to stop spocking its money!!
Finally, you know FIAT money is fake af, right? Federal Reserve is as official as Federal Express... The USD is backed by bombs... And that is sort of the whole point, makes me do what I do! The name Occupy Wallets is more than a good pun... More like, I'll just sit here in your wallet until you figure out what to do with me!
Okay, well good luck with your art-project! I partly agree about fiat-money, people that think that things like blockchain and bitcoin is weird and "scammy", should investigate how "normal" fiat-money is created, to get some perspective on things...
I have an eyebrow raised at the AI-Blockchain connection too!
My latest (not to be taken to seriously) "conspiracy theory" is that Shatoshi Nakamoto was some kind of rouge AI-program trying to free humanity... I guess "I want to believe" in blockchain and this new monetary system as some kind of saviour... I guess people need things to belive in... We all need hope for the future...
Have you heard of Tyler, Texas? It is like AI-CIA headquarters... And ironically separated but not really, a wikipedia search says the patentholder of bitcoin is some guy that comes from the intelligence community, from or at least now living in (You guessed it!) Tyler, TX...
Well you have to be mighty intelligent to come up with something like bitcoin, ha ha ha!