Luffy was handling Kaido by himself. Distracting him so the others could blitz Big Mom.
And I think that's a very valuable thing.
IF, that's part of the plan.
If he just acting on his own, while the others have to come up with a plan by themselves, then we dont have 5v2.
We actually have 2 Yonkos fighting 4+Luffy. It's a small detail but kinda makes Luffy looks bad.
A team fight, but one dude simply doesnt act like a team.
And considering he is gonna get the most shine in the end, honestly, just leaves a bad taste in my mouth.
But don't worry. All of this can be irrelevant depending on the panels and the actual context.
:P