A story is not a concept, but like a great concept, a great story has an independent significance, separate from any novel, play or film that relates it. It is an intermediate form: neither concept nor finished work. Is it ever sufficient to tell the story rather than creating an accessible version of the movie? Is it ever sufficient to offer the screenplay? It seems pretty clear that the answer to both questions is no. The presence of a strong narrative and narrative flow makes compromises like captioning and video description bearable. 'Story' is such a fundamental cultural feature that it has many different manifestations across different modes. A story can be read in text, heard in spoken language, and watched as a performance, and so the story within a work is perhaps the most portable and translatable chunk of content in a narrative work.
A narrative, even when clearly present, is sometimes nothing more than a bit of twine to hold something else more important to the artist together, or to keep the audience distracted while the artist constructs some unfamiliar experience for the viewer. Films that are more poetic and less narrative-driven, like those of Andrei Tarkovsky, which tend to be long and include very extended scenes of slow panning or minimal movement, are astonishing and powerful to watch, but would likely be unbearably tedious with description replacing the visuals.