To me, traps are not for killing - I use them to hinder the enemy. If enemy falls into a trap, it can't hit you, and if it can't hit you, you are one step closer to winning the fight without losses. Simple as that
As for the demonologists, well, if that demonologist demoness in Atrixus had no demonologist troops, I would have had her change her profession
But then again, no Call Collosus scroll for me yet.