It would be too repetitive for drawing I guess (Zoro neither used that one which was used against Pica anymore, or Luffy didnt use a KKG for the second time and overall author likes to renew the moves, so many of them we don't see anymore or barely).
On the other hand, it's a technique used near the ground and Zoro finished King in the air. Finishing King in the ground would have let him there and he needed to be thrown away like Queen I guess.