It requires 2 Energy to be used, and at the grassroots level, your 2 Energy will get you 100 DMG, provided both are heads
The best part of the spell is that you can cast it at instant speed, letting you drop Sphinxs Revelation at the end of your opponents turn or in response to an attack, letting you draw a bunch of cards or keep your life total up above the danger zone
Specialty T206 references also note that natural size variance can exist in unaltered examples
Its rare that Red decks get draw like this, especially when its also mana advantage, and doesnt use the exile zone like impulsive draw
Simultaneously, her +1 ability gives a second life to your enchanted Permanents, allowing you to use your attackers as blockers and stockpile additional Mana from your enchanted Lands