......You didn't realize this?
It's a new game+ option. Many JRPGs incorporate this into play - Chrono Trigger allowed for a New Game+ with alternate game endings.
Playing over is the only way you can unlock the Extreme Power Gamer (lvl 60char) achievement. Not only this, having a fully leveled-up character allows for extra charm/intimidate options early in the game, so you can get some extra sweet dialogue in the game.
Back from the dead, I'm afraid.







