I think the inca warchief aura is very monotonous and not that usable .
It boost ur native units . But Inca can’t make native units by default , they need to make tp on natives to make use of this aura . But native tp rush is not the best stretgy in rush game , they have age one card that allow u to train Carib and few other units , but that stretgy is not great either as those units are not that good for that much investment .
In treaty game , it’s super uesless aura , as Inca don’t even have wood to afford their own units , native units just make it worse .