Ni Gorilla is a "mode" too, should Zoro do gear stacking with Asura and Ni Gorilla on Shishison so he can slice three times with 1 blade and 2 fapping arms?
Asura doesn't provide a flat 3x multiplier to his damage output.
I think Oda realised he messed up with the concept of Asura shitting on the concept of 3 sword style which is why he has minimized/ restricted it's usage it is going to be reserved for a situational finisher only, and his Ougi is probably stronger in most cases.
This is debatable, or else why didn't he use it against Oars or Kuma?
His moves are situational, shisonson is his best penetration quick slash, sanzensekai is his best AoE.