That is a great question... I could be off a bit here because I have looked at static site generators and blogging systems and only like 1 wiki setups (tiddly).
I get the feeling and someone else who knows more should say I am off base that static site generators/blogging systems are easier to setup/use/customize?
But yup I agree with your question, why not use a wiki... and I think the answer is interesting.
I use tiddlywiki's node server and markdown plugin (behind a yubikey auth setup with nginx). It means that the data is stored in markdown files in a folder (with accompanying blah.md.meta files tiddlywiki maintains) but I can still edit easily from my phone, multiple computers, etc. there's a command to load files in (get the meta files and index in place), so I was thinking about using inotify to monitor a folder to be able to slurp in files from there, but I've been happy just editing through the browser and sometimes grabbing the .md files for use elsewhere.
again, the killer thing for me is the portability. vim in a terminal is only nice when I have a keyboard; if I want to keep track of a movie a friend's recommending when I have my phone, being able to pull it up is great.
also, plugins are key. org-roam has this for org-mode, but I haven't seen anything for vim that's as smooth as the backlinks setup I have in tiddlywiki, which is something like https://giffmex.org/gifts/tiddlyblinkexample.html
at the bottom of each note, autodisplaying snippets of context from other notes around links to that note. I also have it display a list of links to notes tagged with the name of that note. none of that is in the markdown files, just the view layer.
I get the feeling and someone else who knows more should say I am off base that static site generators/blogging systems are easier to setup/use/customize?
But yup I agree with your question, why not use a wiki... and I think the answer is interesting.