Cooperative storytelling is something that I have always found great value in. With the amount of time I have spent playing dungeons and dragons, I feel like it is one of the best ways for people to come together and create something amazing. I am relating this to table top games as that is what I have the most experience with, however there are so many more kinds of cooperative storytelling. Improv theatre is one of the types I always find the most entertaining to observe, as it shows just as much about the person or persons taking part as much as it does the story.
With different people, or even just a different combination of people it can completely flip the story on its head. There is a similar effect with table top games like dungeons and dragons. The different party members each play different characters, so a group of charismatic adventurers would play a situation differently from a group of strong warriors, who would in turn play quite differently from a group of wizards.
All of these stories could be just as good as one another, it just depends on the situation. This is the beauty of people coming together to tell a story. A dungeon master can create a world that seems full of life and wonder, but nothing will ever come of it without the help of some incredible players. Critical Role is an excellent example of this, which is a group of dungeons and dragons players that consists of some big name voice actors that has been running for half a decade or so.
This has brought their characters a real personality as they all have their own voice, facial expressions, etc. Matthew Mercer, who you may know as the voice of Mcree from Overwatch, runs the campaign, and has an amazing world set up that could technically exist on its own, but it nothing without the players. All of this ties in to this idea of cooperative storytelling quite well as there is as much of a dependency on the players as there is on the world.