If you use it with Illusionist's spells you'll be able to magic/physical attack all enemies, so apparently it's pretty hax.
Holy snaps. xP It's like the new Calculator or something. xD I'm looking forward to that because my Seer is also my Illusionist. :P

I've mastered some more jobs. Black Mage and Hunter. I guess that makes three jobs I've mastered now. :P