No yolk: Probably a holdover from my dieting days (lost 70 pounds in 6 months with a hardcore healthy, non-cheating, volumetrics assisted NS diet). I found that mixing a pint of eggwhites (buy them in liquid form) with about 4-6 servings of veggies was an incredile infusion of protein, bulk (like a whole minimeal) and had very low calories. And tasted good. Adding in yolks would reduce the protein and up the calories (assuming I keep the volumetric amounts similar).
Liquid egg whites are not paleo. The egg yolk is the most important part of the egg. The egg yolk as as much protein as the egg white and most of the eggs nutrients. Paleo eaters are definitely not afraid of a little fat. If you are, and you want to try paleo eating, get over it.
I am not, nor have I ever been a paleo eater, in anything other than happenstance. And eggwhites rock for those who need to do serious, serious weight loss. I'm talking clinical fatties. I know these people backwards and forwards. They are a whole different breed than you lot here.