ToME: the Tales of Maj'Eyal

Do they do anything to magic-based conditions applied to you?
Do they benefit antimagic users in general?

To my knowledge, it just gives a chance for spells you use to randomly fail, and beneficial magic effects have a chance to be removed. I don't think it provides any advantage.

it does disrupts sustains, although i do not think "timed effects" are affected. otherwise, it would have to disrupt the negative ones as well.