A standard often contains many more options than can be implemented altogether. If each vendor implements only a subset of options, there is no guarantee that any two vendors will implement the same subset. An important pragmatic step is to identify a common subset of options and related practices that can be used effectively. This is the purpose of groups that promulgate functional profiles. Standards are often meant to operate in areas of very different scope.
Profiles provide a framework within which the standards function.
For example, a document archive system may need to function at many different levels. In addition, for viewing or printing purposes, there are font issues, and for document interchange purposes, all the above affect the system. Standards exist for each of these domains, and profiles provide guidance for their use. One key goal of the CALS project is to reduce the use of paper, and this goal has been embraced by virtually all participants. We're not talking about eliminating a few notebooks, either.