When designing a world as a setting for replaying and storytelling, condensing your concept down to an elevator pitch is a great exercise. Not that you’re likely to corner a venture capitalist and a Hollywood producer in an elevator and pump them to invest money in your idea, but because you are going to corner friends, players, and readers and ask them to invest something even more precious than cash in your creation—their leisure time.
I can’t talk about elevator pitches without declaring how much I hate the term. Once that proletarian complaint is out of the way, I’m ready to proclaim that the elevator pitch is a great tool for sharpening up a product.
Did I say “product”? Absolutely! Even if your worldbuilding effort is entirely for private consumption, treating the work as a product is constructive.