I'll be odd man out.....well.....sort of.
For "me" an outside kitchen would be a PITA. I like to cook things like bacon and hamburgers and stuff that spits and splatters all over the place. That stuff goes EVERYWHERE and gets on EVERYTHING! If I had an outside kitchen I would spend half my vacation cleaning up the outside of my trailer and kitchen area. Nope, not for me.
If I cook on a fire there is nothing to clean up besides the pan. (besides, food tastes better over a fire; everybody knows that!)
I don't really like to eat outside anyway. I always have to fight with the bees and fly's and nats and ants or whatever over my food.
Speaking of ants. Ants LUUUUVE grease and can smell that stuff for miles. They will walk to the end of the earth for just a drop of the stuff. Where are they likely to find it? Yep, outside kitchen!