People who are very skilled at something often employ complex strategies, which are, in essence, combinations of scriptlets, packaged so that the understanding of how they fit together gives their user the reputed skill.
Cases typically serve to illustrate points about how to behave or how the world works.
Sometimes, however, cases are simply used as reference points that are part of the common culture. The Battle of Gettysburg is a case. It might be used to illustrate one or more particular military points, or to tell us something about history, or it might simply be used as an example of something all Americans know about. Cases can typically be described from many points of view. Given that one can effectively pursue only a few processes, it makes sense to pick very high-level ones.