Why is South Park made in a 3d App (maya)?

[SIZE=2]What advantage does a 3D animating program give for doing South Park over a 2D animation program? South Park uses Autodesk Maya to do what is essentially 2D animation. After all this time and success, what is the advantage to using a 3D program in doing 2D animation? If you say “because it is what they are used to,” don’t bother answering.[/SIZE]