The value of having someone who depends on your code

"Do you really say there a value in it??" you might say. Yes it is.

When I was studying I delivered assignments to the professor or my supervisor, and no one depended on the code I wrote. When you work on a bigger project, or like me; work on a framework, You have people who needs your classes, modules or projects to work and have the features they need to accomplish their goals.

When you write code and form your projects without anyone depending on it, and code and school projects no one is going to use, the work will never be tested in a real world scenario and you never get to know what the people using your code is going to need.

When a new module such as a REST API is planned before the implementation is done, the group or person designing it will have an idea of how to specify the API. But it will not be finished until there has been a real-world user of the API, someone creating a client application.