Trust me, it's definitely useful in invasions. [He tries to make it sound casual, but there's something a little too serious about his gaze away. He's used magic on both sides of an invasion, much more as the invader trying to save the world than the defender of a school.]

But I haven't really seen any alien overlords or whatever around, so it looks like you guys did okay for yourselves.

[Which isn't to say he hasn't seen any non-human off-worlders, because he has - they just don't seem to be bossing everyone around or as triumphant as he'd expect for a successful invasion.]