Sorry, I wasn’t clear: by “submitting” I meant a pull request to the repo in which this lives, not posting to the forums.
I suppose the reasons about discussions not being ideal for docs are the same as the reasons for the “discourse docs” plugin, which plugin seems to address all those reasons very well.
(As an aside, none of this has any relevance to the original question I posted about, which I think nicely demonstrates the problem I was getting at! Irony time.)