Fizz Hybrid, Fizz Bruiser, Fizz AP

Currently, i prefer Fizz Bruiser, I max W first, either go for Armguard or Abyssal first, CDR boots, Frozen heart, situational items, basicly going 3 offensive and 3 defense items.

i can see why someone go Fizz tank top, a fizz like mine, or AP fizz. Why would you go 21-9-0 tri-force + botkr rush fizz... I've seen this build sometimes in SoloQ and i saw it saturday with Balls. Why is this build working, what is the goal? i feel like its weaker than AP fizz (as talking wich of 2 offensiv fizz is better). Is it a overall team mix dmg? splitpush related? I understand top tri-force fizz then full tank but this one... nah.