If the ontological argument were sound, it would show not merely that there is an omnipotent, omniscient, and morally perfect being, but that it is necessary that such a being exists.
If the ontological argument were sound, it would provide a rather decisive refutation of the argument from evil. For in showing not merely that there is an omnipotent, omniscient, and morally perfect being, but also that it is necessary that such a being exists, it would entail that the proposition that God does not exist must have probability zero on any body of evidence whatever.