Allow editing of property values from a view
Many times a document class may have a series of properties that are simply a checklist of items that need to indicate if they're done or not. These don't rise to the level of a workflow stage as you may have several tasks that need to be accomplished simultaneously within a single workflow stage. To make it easier for those assigned these tasks to indicate if they've been completed, being able to edit those properties from a view and autosave the change would be faster and easier than opening each document, editing, changing and then saving the document.
Imagine it being like changing values in a spreadsheet, quick and easy.