It grants a players lands the ability to tap for two colorless mana, but only if that mana is used to cast X spells
Theres a lot of cards in the deck that benefit from having and playing this character type
Nahiri, the Harbinger is one of these gorgeous cards, and features the lithomancer swinging lava swords at her foe
I could definitely see Struggle // SurviveStruggle // Survive being Signature Cards on EDHREC for Mina and Denn, WildbornMina and Denn, Wildborn and Omnath, Locus of RageOmnath, Locus of Rage
So two things your opponent will have to do when they see Mickey Mouse Inspirational Warrior in play, avoid having an exerted Character and banish Mickey Mouse Inspirational Warrior through a ping damage card
Cards that exile multiple cards at once, delve creatures like Tasigur, the Golden Fang, or persistent graveyard hate pieces like Unlicensed Hearse can maximize value from these mechanics