Weakness To Elements (Desto Staff) Questions

Dagoth_Rac

1). Does Weakness To Elements affect all frost/fire/shock attacks? Or only attacks from the desto staff skill line? In other words, will I do more damage and get magicka back with the Elemental Drain morph + Sun Fire from the Templar class? Or is a fire attack from my class skill line excluded?

2). Does Weakness To Elements aggro mobs? Or, since Weakness To Elements does no damage on its own, does aggro not begin until you actually attack?

Koshchei

1) All.
2) It doesn't generate threat by itself, but if your weapon enchant procs damage on the mob when you cast it, you will pull.