Yes, but if you have one user taking care of one area, you would end having as many groups as users and no inheritance in levels at all. In my app you start setting default permissions to true just to change his own password any assign only the permissions needed for that user. If you have enough users to group them in groups then I agree with you, but it still lacks inheritance to say "editor or higher in this area", how would you mix both approaches?
Or do you focus more on explicit permissions like "can_do_x"?
How whould you apply it in a per area basis more like saying "can_read in news_area"?