On the effective early use of Pretenders in combat

[Firebreath]

Forgive me for asking. But is it really likely that someone would bother building lots of astral mages and telling them all to mind duel....when most of the time that your fighting the enemy won't have any astral mages in their army, or if they do - you can't be sure of it beforehand ,so you'd be wasting your time (unless you're at war with an astral nation, but there arn't many of those...)