Self help usually doesn't teach you anything that is new. Usually they just repackage the same common sense that you've heard a million times before in a new way. That doesn't mean it is useless though, I have had my own life changed by several self help/business books.
Sometimes you just need someone to tell you common sense in the right way so that you actually listen to it.
You don’t come out of the womb with common sense. And you don’t know all common sense possible.
What if you are raised in a toxic environment? Many are. The news media is also packaged in such a way as to cause fear, alarm and misery. Sometimes you have to break free of that. There is a lot of bad advice out there especially in the modern world.