This damage can be used to remove creatures and planeswalkers, or to ping down opponents
After returning the energy attached to the opponent's battle Pokemon to the hand, you can attach energy to your own battle Pokemon
By now, Ive lost count of the number of friends who have approached me with wide-eyed enthusiasm and told me mate, you need to play Hearthstone! Any digital card game exists by default in the shadow of the Blizzard behemoth, and most newcomers have failed so much as to nip at its ankles, many of them withering in the darkness despite being quite good
Lands, utility creatures, artifacts, enchantments all fair game
Because delve isn't an alternative cost, it can be used in conjunction with alternative costs, such as flashback
Similarly, legendary creatures that care about the ping effects enjoy cards like Burning Earth (Ob Nixilis, Captive Kingpin or Ghyrson Starn, Kelermorph, for example)