the Steem blockchain forum, circa 2016 introduced a standard markdown formatting (it's ok, but links are confusing syntax) and thousands of people were gleefully learning how to do it
but as a simple plaintext-that-can-become-richtext it's not the best, and it's notable that github is now supporting asciidoc, which will be unfamiliar, but has a lot more simple and important things (like admonitions, for example, eg NOTE and WARNING and its got a built in table of contents generator, in comparison, there is a dozen different "flavors" of markdown and more or less only github-flavored is widely known and understood
since it's mostly for writing longer form articles anyway, and there are rich text editor widgets available, the problem for normies doesn't really exist
not rendering normal kind 1/1111 notes as markdown is stupid because they are the same unless you put in the # header prefixes and the *emphasis* and **bold** etc and people already do a lot of these anyway, they have become common idiom
but for whatever reason, nostr client developers have declined to parse all notes as markdown, and as such we can't have nice links or sections in somewhat longer texts, no bold, italic, no plaintext or quoting (very helpful for technical discussions)