General questions and discussions.

A specific battle example would be helpful. The idea is that he uses this ability only if it is clearly better than a regular shot, taking into account the enemy's response and everything else.

Tarnum ambushed seven squads of seven Storm Elementals each with ten Wizards and all his machines; the battlefield is bisected by a ridge from edge to edge.
Round 1: Wizards cast Blessing on themselves and the ballista, eliminating five out of seven elementals in the first squad. The first squad shoots, the second and third move on foot, the fourth shoots, the fifth and sixth move on foot, the seventh shoots, after which it is destroyed by the ballista's shots.
Round 2: Wizards finish off the first squad, the second moves on foot, the third shoots (from the middle of the field), the fourth sets off, the fifth shoots (also from the middle of the field), the sixth reaches the tent and is destroyed by the ballista.
Round 3: Wizards kill the third squad, the second reaches the cart, blocking the Wizards, the fourth reaches the ballista, the fifth reaches the tent, where it is successfully turned into mush.
Round 4: Wizards heal themselves and the war machines, manually kill the second squad, the fourth takes its place, damaging the cart, where it is hit by a ballista shell.
PS: The elementals were shooting at the Wizards, who were saved from death by the tent.