ex-death just wanted to send everything to the n-zone. that's pretty mean I think. or evil rather xD Better to live under a tyrant you can one day overcome than to be sent into nonexistence and never live again :O
FFV's final dungeon shows that it's possible to survive in the Void without necessarily getting absorbed into nothingness. And considering nearly every other villain wants to annihilate humanity outright, mere banishment seems like a bargain.