Reveal Magic -- I absolutely do use this... especially in my Priestess book.
Think about those times when you have only enough mana to cast one spell from your Mage, and/or your opponent has an enchantment face down that could wreck you (Forcefield, Lion Savagery on Cervere, Nullify or Arcane Ward, etc.)
And then there is the life gain for the Priestess, being a Holy Incantation....
One other thing... consider using RM on your own facedown enchantment if you end up without enough mana to reveal on a mandatory reveal condition that might come into play later that turn... it preserves your enchantment.