For the Spellbook archetype, this card is pretty good. Don't get me wrong, it's not great; but it can be pretty helpful, especially with his special summoning ability from the graveyard.
Since the you go through Spellbooks like no other with the Spellbook deck, Prophecy Destroyer can easily get himself out from the graveyard a few times. However, summoning him is kind of tough.
First, you don't want to draw this card. What you want to do is either mill it into the graveyard, or use Temperance of Prophecy to Special Summon it from the deck. This way, you end up with a Spellbook card in the grave, Temperance is no longer on the field, and your deck is thinned out.
However, if you are going to use Temperance of Prophecy's effect, you might as well go for High Priestess (if you own her).