I used Worldanvil, and I've got such mixed feelings about it. I think it's probably great for world designers, but can be really clunky if you use it for D&D and have any more of a world than a single province. The learning curve is ferocious !
Although I've still got a subscription, I think it's an expensive luxury I might stop next time it comes up for renewal. Word, Excel and good old fashioned pen and paper work just fine for me 😀
Yeah, back when I was a mod of r/worldbuilding, they'd approached us very early on to partner and I was just... not super impressed with it for my own needs. Its good for what it does, but it didn't fit my style of building that's for sure.
They're certainly good at getting collaborative deals which help their marketing ! I found that after signing up, there was a lot of junk on the screen trying to encourage me to join all kinds of contests and social activities they do. I guess people like that, I'm more anti-social and just want a tool that helps me run my game, not give all my setting info away for free !