As I understand it, KillAndAction means that it's difficult to rush Necropolis because of the large number of low-level monsters + raising the dead, and essentially you can rush with them, but it's not recommended, as there's a higher chance of winning in the late game.
Regarding Orcs - it depends on the situation. Berserkers are usually cast at the beginning, and here, Frighten will be very useful, as the side and rear paths are blocked, and they will most likely run towards the enemies. Also, it depends on the obstacles on the battlefield. We scare the subordinate stack and reduce their Intuition.
P.S. Regarding Necropolis, correct me if I'm wrong.