Why you may ask?
1. Sanji is currently headed towards either Yamato or the Scabbards, I think Yamato is the more likely option and Yamato has stated she wants to fight Kaido as Oden but she cannot go as long as she has MOMO with her.
2. Sanji wants to protect Momo, he will take over Momo so that Yamato can go to the rooftop and fight Kaido.
3. CP0 Leader is afraid of the DEVIL FRUIT that Vegapunk created, if he learns MOMO has eaten it, he might try to KILL or CAPTURE Momonosuke, leading to a fight between him and Sanji.
4. Sanji has always had a thing for being sneaky and acting in the shadows, him fighting CP0 would showcase the power of the RAID SUIT against a rokushiki opponent.
1. Sanji is currently headed towards either Yamato or the Scabbards, I think Yamato is the more likely option and Yamato has stated she wants to fight Kaido as Oden but she cannot go as long as she has MOMO with her.
2. Sanji wants to protect Momo, he will take over Momo so that Yamato can go to the rooftop and fight Kaido.
3. CP0 Leader is afraid of the DEVIL FRUIT that Vegapunk created, if he learns MOMO has eaten it, he might try to KILL or CAPTURE Momonosuke, leading to a fight between him and Sanji.
4. Sanji has always had a thing for being sneaky and acting in the shadows, him fighting CP0 would showcase the power of the RAID SUIT against a rokushiki opponent.