>That story was only there because you were yet to break it down into tasks. Not exactly. The story is there to document something you want the software to do,

>That story was only there because you were yet to break it down into tasks. Not exactly. The story is there to document something you want the software to do, phrased in terms of the value to the user. Once you generate a list of tasks from it, you still need to actually execute the tasks and see if by completing them, you deliver the desired value as expressed in the story. So no, you wouldn't destroy the story once you listed tasks. Once the tasks are done, you still need to circle back and either verify that the goal of the story has been achieved, or that the story is no longer a valid statement about the software.