JE: Not to belabour the point, but is it the actual "sound" that is important or the "breath" that is important? I've heard some say that the sounds help you attain a specific frame of mind which better facilitates cohesive body+breath expression. However, just like how a person can be extremely angry and frustrated, but perfectly calm and orderly in action, how important is sound to purposefully foster that state of mind/body unity?
As I mentioned above, and perhaps I misunderstand you for it may be your point as well, the exaggerated sounds are good as a starting point to help you recognize the breathing and body mechanics...but ultimately they are like training wheels; you need them when you first learn to ride a bike to help you gain that sense of balance, but then you take them off and you can still ride your bike perfectly as you did with the training wheels.