After the recent request by Geoffroy, and after feeling an increase in off-topic questions about cryptocurrencies, I decided to look into it more.
As it turns out, the current statistics for our close reasons look like this (over 187 closed of 988 posted questions; stat access is 10k+ rep exclusive):
|Reason||Questions closed (90d)||% of closed|
|Ciphertext Analysis / Review||26||13.9%|
|Migrations (none to cryptocurrency sites, 14 to SO)||32||17.11%|
|Homework / Puzzles||23||12.3%|
|Custom (referring to cryptocurrency-related reasons)||18||9.6%|
Based on the fact that a generic cryptocurrency close reason would therefore see as much usage as one of our current default reasons (without investigating the generic custom-used ones like "this has nothing to do with cryptography"), I think it is reasonable to have a fourth reason for it as the programming questions are likely not going to decline and we do already have rather crammed our existing reasons. Additionally, a dedicated, well-formulated close reason would probably guide any askers more than the current ad-hoc reasons formulated by the first voting to close right now. Furthermore, while we could replace the programming custom close reason in favour of a SO migration path, we - the mods - already filter questions before migrating them to SO as quite a few them would just get closed over there and in fact even with our filtering we hit 21% of migrations being rejected (i.e. closed as non-duplicate on SO).
An initial proposal for such a fourth reason could be (to be refined in a dedicated meta Q&A or in answers below):
Questions about non-cryptographic aspects of cryptocurrencies are off-topic. This includes financial, economic, and legal aspects as well as questions about the usage, recovery or non-cryptographic operation of surrounding tools, websites or smart contracts.
Thanks to DannyNiu, Maarten, and Geoffroy for the improvement suggestions on the wording.
Answers on this meta Q&A should be used to cover aspects / considerations not talked about in this question (both for and against having a fourth reason) as well as to suggest better formulations for the actual close reason (beware of the 500 character limit though). Answers to voice general support / refusal of this idea are also welcome.