From a higher level view, editorial data and formatting data can be broadly thought of as components. These different components have different people acting on them though, each with their own specialization of tasks.Part of content management, for both editorial data and for formatting data, is the process of handing off data from one actor to another. In practice this isn't an actor per se but a role, a group of actors who intervene for specific functions in the life of a components development.
Since the actions that the different groups take in the course of output development share little in common, it's advantageous to have workflow processes that are independent of each other.