While I agree with Larry's comment, that following someone shows respect to the person, I've used the feature more functionally than that.
If I click under "what's new", and then under "newsfeed", it sifts out the latest posts and activities ONLY by the people I follow, posts, reactions, whatever. This is different from clicking "new posts", where I get unsifted new posts from everybody.
So I guess the aim for following someone is to make a point of selecting which members contribute the content you most value, then follow them for the most condensed, optimal experience on the forum.
Or just ignore that and read all the riff-raff like I do