Question about Lunging Strike Barb build...

This build here inparticular... https://maxroll.gg/d4/build-guides/lunging-strike-barbarian-guide

Why do most builds i see run the Battle Trance amulet if it is made for Frenzy and not Lunging Strike? Wouldn't there be better things that would buff the build instead of an amulet that buffs nothing to do with the build? What am I missing here...