1) Used his DF against Sanji and against Marco.
2) Fought offpanel with Marco for more than 1 hour and against Sanji for some minutes. Offpanel timeframe = you can imagine he used named attacks.
3) Oda only draws some moments of the fight, point 2.
Kaido don't care and much less BM. Simple.
Luffy used it, but anyway like we saw, Sanji and Jinbei were escorting him and tried to let him arrive with the most energy possible for Kaido.
None marine showed CoC, so they don't have until proven otherwise. Irrelevant example. And btw, Shirohige tried, but he couldn't because of his health issues
TobiRoppo only came because they thought Kaido summoned them and it was King.
https://official-ongoing-2.gamindustri.us/manga/One-Piece/0979-010.png
https://official-ongoing-2.gamindustri.us/manga/One-Piece/0979-011.png
https://official-ongoing-2.gamindustri.us/manga/One-Piece/0979-012.png
"Some of you wouldn't bother to show up if you knew that ahead of time, would you?"
Yeah, so muuuuuch respect

.
So what if Kaido consider him the right hand? In almost every crew there is a right hand man.