>>18686655I use this as anti-Deluge tech in my Fire Typhlosion-Delphox Unlimited 150 deck.
Against Deluge who frequently has in excess of four energy on the board, Energy Crush seldom doesn't land a KO vs their Grass weak Blastoises, Keldeos and Feraligatrs. Granted, the second attack is like Mewtwo EX's Psydrive, you just outright don't use it.
As in Unlimited, for balance with older cards the Prime series and BW/XY holos are counted as Pokemon-EX, even if Leafeon takes down PLB-Blastoise or BDC Keldeo, that's two prizes for Leafeon's one, and seeing as the former will usually have 4+ energy on it and Leafeon will only ever have one, it does its job very nicely.
Even against non-Deluge, it's pretty decent as a revenge killer against decks that like chucking Energy everywhere.