Robins logic: Sanji relying upon me for help means he is truly worthy of being a wing of the PK.
In other words, complete nonsense no one has to agree with. It's just robins opinion. Or Oda's L train of thought he's implementing into his story. This idea of having to rely on others, e.g luffy needs sanji to be the pk cuz he needs the best cook.
This whole notion of trusting your life to someone else can be heavily disagreed upon, even though oda is clearly calling it a strength when it comes to having a successful crew. That's all good and all but:
But a lot of the agendas people have concerns a characters individual strength from a powerscaling perspective, they aren't concerned about narrative. Even though oda will put the importance of narrative > everything.
Either way lanji is lanji, no matter how strong he gets.