I've seen a couple of these in search results while looking for info about more niche games and at first I thought they were fan made but like the article mentions they're not actually wikis, nor do they contain accurate information.

The ones I came across just contained nebulous prose with variously incorrect info about the game on a few barebones pages, with a custom domain name. They weren't using any wiki software.

I have uBlock Origin installed so not sure if the purpose was ads but I was baffled as to what the goal would be otherwise since they're useless for proper information, let alone a wiki.