Because Marco has no AP to take down king within 1 hour, but zoro has.
It is just that simple.
Marco cannot defeat King, neither can King defeat Marco within a short period of time.
BM needs to be stalled, Kid + Law would not be able to stall BM for long.
so Marco is the perfect guy for stalling.
It makes total sense.
It is just that simple.
Marco cannot defeat King, neither can King defeat Marco within a short period of time.
BM needs to be stalled, Kid + Law would not be able to stall BM for long.
so Marco is the perfect guy for stalling.
It makes total sense.

Marco does not want anything to do with Yonkos; he's clearly promoting the the rise of new generation.
And who says they're there to stall BM? Kidd and Law are there to take down that woman. My boys gonna hunt a Yonko.