Why shojin 2nd instead of hexplate?

My I think of shyv as a pretty ult reliant champ, hexplate's AS lets her get to her Q3 faster and offers a massive AS steroid on top of her steroid ult. Hexplate 2nd (after triforce) just seems intuitive to me. Is shojin 2nd favored bc its provides value both inside and outside of her ult? Outside of her ult you still get value out of shojin passive and inside her ult shojin passive amps Q3's true dmg. Is the basic haste also more valuable than hexplate's ult haste? Is this why shojin 2nd is favored over hexplate?