Nowadays the workflow metaphor is mostly used in BPM  (Business Process Management) environments where a workflow represents a business process and orchestrates a number of existing systems typically (but not necessarily) accessible by means of Web Services-based interfaces.

The workflow metaphor provides a clear and intuitive representation of the process execution flow. On the other hand a purely graphical or descriptive formalism is not suitable to specify all the details involved in a process that implements a piece of the business logic of a given software system.

A usual programming language such as Java is definitely more powerful and flexible to deal with data transformations, computations and other low level auxiliary operations that can be needed during the process execution. Furthermore programmers used to exploit powerful Integrated Development Environments such as Eclipse would not even consider working with a platform that does not provide the same level of support in terms of searches, navigations, error reporting, automatic suggestions, refactoring, debugging and so on.