I'm actually doing a comparison right now. Lemme get back to you in 10 minutes.
Attacking decreases enemy defenses for the next attack, even if your first attack doesn't win, the enemy still has defenses lower than what they would actually have.
You could say that it's the debuff of the game.
Wait a sec, then what's different from conquering?
Conquering also, through combat, lowers the enemy's defenses. Is it at a greater scale? But wait.. successful conquers pretty much destroy all of the enemy defenses(except for half the traps).
Perhaps attacks are for when you know
you are going to lose?