User blog comment:MisterWoodhouse/Introducing Affiliate Marketing/@comment-28991887-20200910183228/@comment-20644-20200910224434

That side rail unit has always had that slot for sponsored content. Initially that unit didn't have any wiki content in it at all, and it was all links to Fandom.com. But we changed that and made it Popular Pages, but we still need to have a spot where we can promote sponsored content in order to drive views and meet revenue goals that help us to continue to support wikis.

I agree it's not ideal, but with the way that the site is currently designed, there are very few options for content promotion. This happens to be one of them.