Blade Vortex Champion?

Saw these two on poe ninja:

https://poe.ninja/challenge/builds/char/iamjustacrazy/MagicFund?i=0&search=class%3DChampion%26skill%3DBlade-Vortex

https://poe.ninja/challenge/builds/char/dvs_m0rph/morph_PAINCHAMP?i=1&search=class%3DChampion%26skill%3DBlade-Vortex

My only question is, does impale apply to BV? If so, could someone have a look at the POB of any of the above 2 links, it says the impale chance is 0, yet they both take master of metal. Why? Wouldnt it be a waste? They are also using watchers eye with impale last 2 additional hit. Yet their impale chance is 0???

Apart from that, any thoughts/feedback about BV Champion is appreciated.

The gloves give spell impale.