This is one of the old issues with XML, that it is used for both data (machine-readable information) and content (human-legible text).

Enter the Semantic Web, which is the vision that the existing Web can be augmented to supplement the content designed for humans with equivalent machine-readable information.

Although they are intended to be human-readable, CDA documents also contain a wealth of machine-readable information, which can be made more manageable by transformation into an expanded client view.