I think, without being an expert or knowing anything of the Zimbabwean banknotes, but I think, if it was made and put into production, an argument could be made to have it in the catalog.
1) To have a more comprehensive catalog. See it as a trails/pattern issue maybe?
2) If some escaped the furnase, and people got their hand on them, it will be nice to be able to look them up.
Other countries also have unissued notes registered on Numista.
At least that's my opinion, especially if a picture of the 200 Zimbabwean can be found :D
I have a soft spot for origami paper cranes.
Read or watch about "Sadako Sasaki and the Thousand Paper Cranes".
Spread a little peace and happiness wherever you go :)