This is actually addressing something that you cant really easily do in other frameworks (or even previously in React). The idea is to return control of rendering to the caller rather than have the component be responsible for fully rendering the entire thing. I.e. a toggle component only knows how to toggle and you can choose what goes in it. Ryan Florence has a much better illustration of why you'd want to do this: https://www.youtube.com/watch?v=hEGg-3pIHlE