Kninjanin, I just happened to see the ads below our answers to your question, ...and one of the ads is for "Buy Follower Social Media," another is "Free Instagram Followers," still another is "Get Followers!"
So idk, maybe that does have to do with data harvesting as Tink and Marianne are thinking? Or - do you suppose some people buy followers just to feel more popular? I never even heard of that before!