No. It's not "Follow". Following someone just means their notes show up in your feed. If they posted something 2 days ago, and you are scrolling your feed today, you will have no idea they posted something unless you happen to scroll far enough that you are seeing posts from 2 days ago, or you actively go to their profile to see if they have posted something.

For most people you follow, that's fine. But you may have people you follow that you want to make sure you don't miss a single post, and for Amethyst, where notifications pop-up on your phone even when you don't have the app open, you could see right away if someone important to you has posted something new.