What is the point of Grays being used as "Shell pilots"

So I've been interested in the whole UFO/UAP phenomenon going on thirty years now and about ten years ago was the first time I heard about the Grays being pilots of sorts theory. From what I gather some people have "evidence" of them being more of a manufactured entity than a biological born and raised being. I guess what I'm getting at is what would be the point? It seems kinda redundant to me. I know that they are not us and we are not them but it seems like an extra unnecessary step to pil...