Ah yes, I happen to be somewhat familiar with Notgeld because I spent many years trading in paper collectibles, particularly old stamps and manuscripts. For a while, people also used "encapsulated stamps" in place of coins. Some Scandinavian towns during WWI also used "town money" in individual municipalities.

The US was somewhat unique because of the geographical size that made currency issued by the local bank of a frontier town the de-facto money there, because the idea of getting federal currency was impractical.