To me it's not even non-technical users, or juniors: this is a way of documenting components and their important substates, the same way a CSS styleguide does. It can help keep consistency of use, document features and states that may be overlooked by a consumer, or act as a framework for design QA.

It's not even just documentation - you can use it like visual unit tests, so you can see what the effects of a change are to all the different states of a component.