These buy time for Lorehold and the miracles to do their thing: Overwhelm the table because you're either spending more mana per turn or getting more value per mana spent
Coretapper also speeds up charge counter production, with a sacrifice ability that lets you put two charge counters on a target artifact
It has many defensive cards like Guard Point or numerous counter 2000 cards that help it survive, board management with Marco or the recently added Nico Robin (OP05-010), and significant pressure with Luffy, Ace, or, if you draw it, the monstrous Newgate, which increases your leader's attack points by 2000 until your next turn
Pokemon TCG is one of the easier trading card games to learn, and its win conditions are usually pretty straightforward
Since Derevi makes it easy for you to untap your permanents, it makes it so you can play permanents that prevent other permanents from untapping and making them only affect your opponents and not yourself