When Sparkling Crystal is attached to a Tera Pokmon, which Dragapult ex is, that Pokmon's attacks cost one less energy , allowing for Dragapult players to use a strong move like Phantom Drive much sooner, or even use Jet Headbutt without needing any energy at all
You can just use it at the end of your foe's turn and then untap and go on
This Booster Pack contains cards like Dragonite VSTAR or Mewtwo VSTAR (Regular and Secret Version), Rainbow Cards, and of course, the Radiant Venusaur, Blastoise, and Charizard cards , as well as the infamous PokeStop Stadium and Snorlax cards that are often used for the Stallax strategy
there are only a few mono-Black ways to tutor for a Swamp
Granted, U/W/R has ways to beat any and all of these cards, but its difficult for the opponent to have them all at any one time
A card is only worth it if you have a plan for it