Perhaps the intention is not necessarily to have multiple renderings or interpretations (a very specific feature that not many people would exploit but would be interesting to have), but to make the DNG file specification open and adaptable enough so that any camera manufacturer can embed the camera information that manufacturer wants?
In other words, make the DNG format friendly and adaptable enough, so everyone will sign up?
[edit - another thought]: it could also allow the end user to attach different types of "corrected" camera profiles.
Andy