Even for spellcasters, the level 19 skills are kind of... odd. I mean, they look cool, and rain destruction down upon the battlefield, but they also have a very strong tendency towards friendly fire. They're only really good if you have several characters with immunity to particular elements (more than 100% resistance) and don't mind putting negative status effects on your guys (or just have really high Bodybuilding/Willpower).
They're normally not worth it. To be worth it, you need to build around them, which means you'd have to know what they do prior to character creation. This isn't likely.
Last edited by ScrotieMcB; 29/07/14 12:04 PM.