The AI will frequently throw units at you one by one instead of mustering a proper attack force, units attacking buildings will keep doing so even while being shot to pieces by your troops. You can even get Darth Vader versus Anakin Skywalker.

Without proper escort, they have no answer for melee units. note And speaking of bombers, they also get bonus damage against turrets - including, strangely enough, Anti-air turrets.

Naturally, power cores have low HP and bombers get bonus damage against them.