If we're assuming AI successfully produces what it is asked to produce, simply having the execution of the story done by the AI might be enough to entertain the user. Additionally, they can use it to then entertain others, where those others feel like they're taking a ride on the prompt writers story.
However, I can't imagine such a story having the depth needed to really entertain the same way that a movie would. Additionally, anyone that isn't looking for depth might not be bothered to write a prompt. Unless it's possible to generate hours of video from a single prompt.