I am surprised this is legal because I thought currency was property of the state. For example melting low value coins for their metal used to be illegal. I know that damaged currency can be traded for new currency at the appropriate banks.
I get it is art, and I dislike it :)
An unusual property of this mechanism of creating a stablecoin is that the bank no longer holds the funds that back the stablecoin. There's no possibility of the bank locking up the funds of a company that issued a stablecoin.
It's the burn and mint used in Luna Classic, now in physical form.