Ok, I haven't really tested it, I always thought the perks were pretty much a waste as well, but in a way, its almost like increasing your damage. For the lightning spell it especially is, as your enemies will die at 15% less health, but even for the fire and frost ones, they make your enemy stop fighting at an extra 20% less health Yea, you have to finish them off, but with them paralyzed or running in fear its not too hard since you don't have to worry about the threat of an attack, which neutralizes them, making it easy to mop them up. it gives you time for your magicka to regenerate if need be and you can just wipe them out.
I know a lot of people don't like the fear effect from fire, but as a mage, fear is one of the best effects you can use, same with turn. Going into a Draugr dungeon with a turn undead spell in one hand and a destruction spell in the other is great. As a mage having your enemies turn tail and run just gives you more time to line up your shot and blast them down with a spell.
anyway, just a thought I had, agree/disagree?