you cant spend them on your costs
And then, of course, there's a level deeper
After the first set of cards in Legends and a few other sprinklings, many of which established that gold cards would be consistently more powerful than their competition, gold came into its own in Invasion block
With tokens - treasures or dragons - or just dragons you don't mind going to the graveyard, you get a lot of fuel to not hurt yourself, and if you are able to manipulate the top card of the deck, you can use him as a cheat into play engine, while still working as removal that also get past indestructible
Card Name Mana Cost Type Enchantment Aura Rarity Common rules Text Enchant creatureEnchanted creature has base power and toughness 0/2
With the right combination of cards, it's possible to lock your opponents out of even playing the game