Its like Cards for Black Feathers for Fairies, this might give Herald of Perfection decks greater speed, allowing them to accomplish their lock faster.
It could allow you to get rid of those dead vanilla fairies from your hand.
Its drawback of not being able to special summon on that turn may be lessened if you play Pot of Duality on the same turn. You could always wait for the next turn to special summon your Herald or Christia and maybe you could draw into a Royal Decree to protect them.
Luckily, its drawback of not being able to enter the Battle Phase does not affect the deck much.