A use case is formalized from User Stories in the context of attempts to realize best cases. A complete use case analysis also depends on worst cases and actual end user feedback - the status quo of what Consumerium Services actually are, and are doing in the user's context.
It is also framed by visions and threats, to the degree that some objectives are dismissed as infeasible even long term, and some issues are dismissed as irrelevant by those who deem them to be 'impossible'. The main value of explicitly stating these is thus to ensure that best cases and worst cases actually represent what analysts really believe can or would happen. However, in case there is later disagreement or change in beliefs about this, the visions and threats (and all stories) must be maintained, especially to achieve a dissensus.
There is a long history of use case analysis as one of the software development concepts that arose alongside object-oriented programming. It is thought to have formally originated with w:Ivar Jacobsen in Sweden, but its roots are deeper and intermingled with CRC card, test suites or other means which focus on simulating the behaviour of systems before they are built.