Rogues are different from BP's, and use a different technique.
Illusion is still a debuff. Legcut is a debuff. Getting slowed by glacier is a debuff - I'm not sure how to count getting stunned by light or messed up by scream, blind is certainly a debuff, but the point is that every class has debuff type castings of one sort or another.
I admit, I rarely use illusion, mostly I use it in parties with a healer who wants to take it easy for a while, tired hands or whatever. It knocks about ten percent of the damage off what a mob can do to you.