Is it possible to store a component in React state?

Question

React

I'm learning React on a test project.

There is a component Exerciseand its children Set.
When adding a new Setone, it is written to the array: this.state.sets()

But today I heard that this should not be done, but I did not find out the details. Is it possible to store other Components in a State? If not, why not?

Demo&Component code: https://codesandbox.io/s/inspiring-haze-uycjb?file...

Illustration:

Answer 1

Storing a component is a derived state and therefore bad practice.