Having a land that can add two mana is such a powerful effect
Those kinds of matchup are very tight, a lot of cards are basically dead and one life can make all the difference
Fact or Fiction can net you more card advantage, but is also instant-speed while giving you card-selection from the cards in the top five
And keeping Yuma on the field is pretty nice
Acornelia, Fashionable Filcher, Alexander Clamilton, Pippa, Duchess of Dice, Stet, Draconic Proofreader, and Syr Cadian, Knight Owl (this is the only one that makes me chuckle)
You need at least 7 mana from other sources to net a single extra mana from the Cube, and its usually easier to find an infinite mana combo using ordinary mana rocks than it is to turn this into a reliable engine