Correct. But adding the projector will do a few things for you:
1.) Unmatched light output; you'll never get that bright with HIDs alone
2.) Less issues with other people and the law. It will focus the light on the road, not scatter it like reflectors do. Cops CAN pull you over and ***** that your headlights aren't adjusted properly, or other such bs.
3.) It just looks so much damn cooler. Paint the shrouds whatever color your want, add angel or demon eyes, your choice.

I would never go back to stock housings in a million years.