Jude's son is a liability to their crew, only thing he brings is cooking. But that can be replaced by any random cook out there or heck, have someone in the crew learn some cooking techniques and that's that.
Imagine having a dude in your crew that will not under any circumstances raise his hands(or legs in this instance) against a woman, even if said woman is about to kill him or his crew.
Holy shit.
Luffy is so Lucky the Kuja pirates arent antagonistic or else Simpji would be absolutely useless.