I believe he will play more a psychological role.
Kaido and yamato seeing him in his human form will have some impact.
Defence wise could be very useful, he is definitely a psychical beast and could give some time to Luffy if/when it's neede, plus i believe he could absorb quite some damage.
But that is all about him and kaido i believe, yes he have potential to surpass kaido himself but it would be kinda lame to use adv CoC attacks and hurt kaido now...