I wouldn’t do that any more than I’d charter an entire train to commute to work every day.
Yeah, Discourse shares some basic elements like categories and tagging with note-taking apps, but as a forum it has a TON of other stuff going on under the hood that would add nothing as a notebook but overhead.
I can’t imagine what markdown/wiki/notes requirements you have that aren’t served well by, say, Obsidian — but that’s a topic for a different forum.