What's the use of childlike innocence?

How can it be useless? Keeping innocence from the shallowest point will not make you too sad and disappointed.

Furthermore, when you encounter things or difficulties, you will be more optimistic and open-minded. Of course, things may develop in a good direction and difficulties may be solved.

Others vary from person to person, of course, but the impact on people is always mostly good.

So I think it is necessary to keep childlike innocence.