There is only ONE main job on that mantle that would benefit from that augment. So why SE would you even have that as an option for augment on an item like that. Their algorithm for determining augments based on the piece, the jobs that can use it and stats already on the item is just pure lazy coding.
Clearly they want you to get discouraged so less people will get the really pimp stuff. Whyd did I get 4 weskits with divine magic... so I could use it as a blm/whm banish peice lol?