[vanderZwan]

If you think about how they created this from the POV of the game creation pipeline, then that probably is the way. If this is done by creating a shader on top of "plain old" 3D assets, then aside from the programmers/artists involved with creating that shader everyone else can go about their business with minimal retraining. There probably was a lot of content to create, to that optimization likely took priority over other methods of implementing this effect.