I'm afraid I don't understand this *what is the use model for the application that maximizes the functionality you built into it.) question. Perhaps the answer to your question, is that I've focused more on a logical, object centered decomposition of the health/medical information a person would want to track, and less on 'use cases'.
That is not to minimize the value of use cases (which maybe your focus?). It's just to say that different people thing about things differently, and HealthFrame's organization reflects how I think about this information.
I do try to 'overlay' common use cases onto this data model, so that these use cases are optimized (though that hasnt been done as much as I would like).
Please let us know more about what you are thinking here...