wdym it doesn't make sense?
They are not holding back but they aren't using their strongest attack off the bat.
No, not really.
Especially since this was preTS and haki was not visualized.
Kaido was trying to kill Yamato
Mihawk was trying to kill Luffy
That simple. But in Mihawk's case he was stopped by YC5 and could not get past him to get to Luffy until Vista quit and only then Mihawk was able to chase Luffy once again.