Ideas make more sense when visual.
This type of sketch takes 2 min. - meaning, you can make lots of them - quickly!
Discuss through sketches - its easier to understand and efficient to generate ideas.
Here is my reasons why the app "North Sea Movie Maker" won an award. They directed the app value to the tweens, bored at the Aquarium in the North of Denmark.
The app has movie clips ready with animated fish that slap you in the end. With augmented reality, which is a fictional video overlay, you can film the fish slap your friends. Quite subtle action - but it engages the tweens tremendously!