because sanji is the only one to be born with potential to be a conqueror
Thats what i was saying... Like, when Sanji asks Zoro to kill him if he turns out to not be the Sanji they all used to know anymore, he attacks Queen with Hell Memories and i remember very well that the editor's note said "A strike that shows his resolve"
It is still not explained why did Sanji's eyebrows came back to normal, even when he felt in his body and said that the transformation seemingly was already completed. What did he do for that to happen? Was his will so strong that his own self managed to rule over it?
Sanji has so much pride on who he is, that even when he asks himself "What would be more useful to the King of the Pirates?" he simply chooses to keep his own self intact and destroys Germa's main and most strongest power up on which they rely the most to fight properly.
Luffy would obviously prefer to have real Sanji by his side, but its interesting to see that Sanji simply gives no shit to that and would 100% prefer to die if he can't live with his true self.