Allow me to explain.
The most important aspect of a User Story is that it's an independently *schedulable* unit of requirement (feature). The key to achieving the "independently schedulable" characteristic of a user story is that you express it in terms of how a "user" would use it. This leads you to a unit of functionality that's implemented end-to-end (UI to backend) that a user can actually interact with.
Not surprisingly, because of the focus on how a user would think about a feature, a user stories are highly readable - and could very well be written by the users themselves. However, the other important and less obvious aspect of a User Story is the emphasis on communication with the end-user and getting confirmation on the acceptance criteria.
Describing all the requirements as User Stories for a decent sized product is rigoro…