Sooo similarish to story board art I guess. Where you get ideas for character design, scene movement, the flow of one scene into another, etc.
The writer is responsible for the content, then the concept artist develop the characters, then the story board artists develop the perspective and flow of the scene. Then the artists go in and give it its “professional” look, using whichever style they decide to use creating...tadaa! a comic book/animation/video game, etc.