^ The whole intention is to win the war. If a battle looks like it will be lost, one doesn't wish it to be a total loss and let everyone perish, especially if there's an option to retreat where a regrouping would result in sufficient reparations for a more effective engagement the next time around. However, if a particular battle is significant enough where retreat would result in those forces continuing on to reach other combat units, one would continue the battle and serve to weaken the enemy as much as possible, acknowledging that in the end, your unit will perish but the enemy will be weaker on their next engagement with other units on your side.