Thats pretty much how I think of the SubD cage too. Thats more or less the advantage of using SubDs instead of manipulating the polys directly is that you use less data (less time) to control more data.
What I do with those star shaped intersections is use spin quads to push them out of the object to an edge or to an area where they can be hidden or they just dont cause problems (areas that wont be deformed).



