Literature and the written word, with its many strengths and weaknesses of storytelling, often cannot completely convey an idea, a feeling, a setting or a person. While it's true that film, animation, and music all have to be written in some form (mentally or physically) before they're created, sometimes the medium can never be divided from the story. A written script wouldn't do justice to the work of a cast and crew. That's at least my theory as to why film adaptations of books almost never turn out well.
Quand J'ai Remplacé Camille is one of my favourite examples of almost completely non-verbal storytelling. It reminds me of a Stephen Fry quote: "a true thing, poorly expressed, is a lie". The way I interpret this is that, if we want to create anything true to its own narrative (true to itself) we have to express it according to that truth. And I think this story, though short, couldn't have been told any other way.
When a story seems impossible to construct in another form while remaining truthful to itself, that's when I think it exists in its best medium. What does everybody else think?