I try to apply this in my photographic work when selecting what to include or exclude in the frame. If you were to take this into the context of visual storytelling, it could apply in so many areas, especially in selecting the final images for edit. Include what you need and exclude what you don't.
Riffing on the above quote, I found another quote that perfectly applies this concept to storytelling. It's from the late Henry Green, an English author best remembered for the novels Party Going and Loving.