because sanji only development is only in cooking skill no more
because oda hate him and have no interest in making his combat ability betterヾ(╹◡╹)ﾉ~
He can FLY
I think Oda wants to show all Strawhats fighting ability in Wano. And I think he's trying too hard to avoid showing them fighting Big Mom Pirates because he wants to keep some mystery and show those confrontations when they meet again in an other arc, probably Elbaf.
Oda doesn't hate Sanji, that's silly
Wow some people already guessed a few chapters ago that sanji is going to bake that cake for big mom. How did you guys guessed that?! I couldnt even guess not even one correct thing lmao