User blog comment:B214/Question & Answers 5/@comment-67.211.8.19-20150420155100/@comment-1359322-20150421065857

I think there's some misunderstanding here, the Sephiroth Graal doesn't function to revive things only.

"“—It’s the Holy Grail. By being in contact with the principle of life, she is forcefully told about how the life and soul are made and what it really is, the more she uses the Sacred Gear. The information about life is so huge that we think it is endless. She takes in the mind and the concept of the dead, the living, and various other things as she uses the Holy Grail. Within her heart and soul that is. ……Many thoughts of other people come into her heart where corrosion occurs. ……It’s natural for her to become broken.”"

Basically it tells the user about how life is created