Mostly I mean the wikis for really informational subreddits like /r/bodyweightfitness or /r/personalfinance. Those would usually be the best place to get information on whatever topic that wasn't mostly sponsored propaganda. And it had uses that the threads didn't fill because the wikis would take a comprehensive view of the subject matter whereas threads would be about one or another detail.

Who knows. Maybe I was the only one who felt like they got benefit from the wikis. Ha!