elephants rack up many more kills in a shorter amount of time when they are charging.
Yes well, if you had an object the size of a small house crash through a group of people at 30mph, i imagine there would be alot of casualties. And btw, if you can get alot of enemy to gather around you, the elephants can cause quite alot of damage. I was recently fighting a battle against the numidians, were 3 units of their javelin men gathered around a unit of Armoured Elephants. It was a massacre. Within a few seconds, about 200 of the enemy were dead because of the elephants in melee mode. Heck, some of the enemy went flying across the wall.