CAM mode should let you make modifications (with design history) to your Design model that are just for CAM. The most common modification I need to make is to suppress chamfers, fillets, and "unmodel" (suppress) large threads. Often I want all these details fully modeled in Design mode (and Animations, Renderings, and Drawings), but I want the CAM to take care of it when making toolpaths. Modeled threads especially mess with the CAM toolpaths.
This could be analogous to the Simplify mode of Simulations, where you get a parametric design history modification of your Design assembly for simulation.
