It's all about your Hero/Heroine's personality. The Good Alignment is based on your Encouragement vs. Punishment; the more encouragement, the more good the personality.
Having a personality that's in the Good Alignment means your Hero/Heroine is less likely to die, especially since they take less damage from attacks.
This also benefits you as their God/Goddess. The less damage they take, the less God Power you're using to heal them, and the more time you can spend enjoying life instead of wondering if you're gonna have a dead hero
These are the different personalities my Heroine has had on the Good Alignment: Good Pure Virtuous Righteous