we don't get any score for victory in battle...
You may not gain score by killing units, but you lower your enemies score.
If you are in a boxing match and you knock the other person out. You dont gain more consciousness and then win because you have consciousness x2... You take away the opponents consciousness, giving you the victory.
Same goes for battledawn. Take away your opponents score, and you will win.
(Not to mention if you kill your enemies army, you can steal their crystals for score anyway. So even what you are saying about not gaining score for battling isn't exactly true)