Like most energy cards, every card on this list makes energy, and then gives you a way to spend it
Since the Treasures are tapped, we can untap them with Archelos, Lagoon MysticArchelos, Lagoon Mystic or a similar card, or in some cases simply sacrifice the Treasures to Krark-Clan IronworksKrark-Clan Ironworks
Shard of the NightbringerShard of the Nightbringer having a cast trigger is a real disappointment with no way to get it back to hand, and Trazyn the InfiniteTrazyn the Infinite and Convergence of DominionConvergence of Dominion don't really do much in the deck
If you controlled it, return it to the battlefield tapped
Thats why its a good trade for us to exile one card from our hand to get the tempo advantage when we are on a draw Since Gemstone Caverns enters the battlefield before the game starts and the first turn in the game is the opponents, its important to have enablers that will fully benefit from the fact we have this one extra mana source on the turn zero