Looks pretty unreliable, since you have a 50% chance of getting no energy at all.
Though it isn't legal in Standard right now, Fairy toolbox Mewtwo (with Xerneas and Aromatisse) looks pretty much better in every aspect but that wasn't played much iirc. Could try playing it in Expanded though.
If you want to go ahead and play this deck in Standard, I'd replace Gyarados/Charizard with Articuno (with find ice), since it's attack does the same thing as Charizard's one without the coin flip, and you give up less prize cards. Not something that would really get you any wins in competitive play, but you can definitely try it as a "fun" type of deck.