Writers do not rail against the tyranny of the English language and how if it just were not for the words we have to use things would work out much better. No writers complain about the general requirement that stories be about people or personified things. Writers accept many things in their writing that they have no other choice than to accept, but since writers can get by without using story structure some believe it is not useful.
Though writers can ignore structure and still reach some success, story structure has a lot to offer writers that want to wring the maximum expressiveness from their ideas. For writers that want to communicate precisely and not just do whatever they want, story structure can help out.
Like A Sandbox
Without knowing where boundaries are, it is easy to get fascinated with roaming. Artists in general derive much satisfaction from putting their ideas out into the world, regardless of whether the underlying ideas are received. Structure is a fence, it is a sandbox within which it will help get your ideas across to others. Instead of looking outside of the sandbox, why not use shovels, buckets, and water to make something cool right in there. Knowledge of story structure gives you the freedom to not have to worry so much about where you can go and helps you concentrate on where you should go.
Helps Hold Reader Attention
In a certain light story structure is just a gimmick like others. It is a contrived way of looking at human experience, but it is based on a fundamental part of the human condition. Scintillating imagery and explicit violence might keep a reader engaged the first time, but you cannot keep doing similar things story after story because the effect will wear off. Story structure (a progression of actions in pursuit of a goal) is a gimmick that never gets old because it is not a formula as much as a recipe that we all use to sort the events in our own lives and is infinitely compelling.
Allows Innovation Elsewhere
Many writers lament audience or reader inability to accept alternative lifestyles or viewpoints in stories. They wish readers were more adventurous and open-minded and would read this or that story about this or that unlikeable character. With story structure firmly on your side, you can reach deep into the depths of human experience and be sure people will stay with you. Brokeback Mountain was not seen by only gay people, gay cowboys, or fans of alternative Westerns: it was seen by "normal people". They saw it because the story hooked them and they could not stop watching. Structure can give you the ability to engage someone with a story about a subject they otherwise would find repugnant.
Break Rules Skillfully
Not only are there many different words used to describe the same aspects of story structure, concepts are explained in myriad different ways. No single book can teach you story structure and no single guru has all the answers. There is an underlying true meaning of structure and it can only be understood by thorough study of all its facets. This may take a long time and require much effort, but once the foundations of it are understood it becomes a tool rather than a box. Once the underlying principles of all the words and concepts are clear to you, it becomes easier to change rules many swear by that are only manifestations of principles. Once you master the form, you can break rules yet still hold true to principles.
Story structure has such a bad connotation in the writing world, I can understand misgivings about giving it such intense focus. Many believe in structure lies hackdom, overly-complicated plotting, and cardboard characters. Think of it this way: if story structure can help poor writers that do not know how to sketch realistic characters or have little grasp of grammar, it could be even more powerful in the hands of a writer with some real skill.
Do you read books about story structure? What value do you feel it has?