Very little is immune to fire aswell.
You leave out scorching ray from your little comparison, but that's a very nice spell. No save and apart from shiocking grasp it's a ranged spell, so you don't have to run up to the mobs.
An ogre! yea lets go in melee range and kill it! :P
There is nothing quicker about elec/acid, being able to do full damage to fire immunes sound great in theory. But at those levels you meet very few, and you can do snowball swarm or niacs for double damage against them.