Its good at damage against mobs that take, like, 150~200 more points of damage every time a lightning spell hits em :O (Like Bonus 1 Orcs and Jahill raid skeletons), but other than that, that's pretty much it... (Btw, are mobs in Myth 1 Lightning weak? I don't know :O)
It's cool down is way too long for something that doesn't do much and is easily replaced by other skills IMO.