It lets you risk milling yourself out, but can give you a whole host of board presence in the late game
Urza, Chief Artificer Probably the best affinity commander in the game, Urza, Chief Artificer focuses on curving out with cheap artifact creatures like Esper Sentinel, Ethersworn Canonist, and Master of Etherium to make Urza itself cheaper
[10] In 2013, a high quality copy of the card was sold on eBay for $27,302
Spend this mana only to cast outlaw spells or activate abilities of outlaw sources." (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.) Whenever you cast your first outlaw spell each turn, you draw a card and you lose 1 life
It removes the deckbuilding barrier entirely while still giving you a real Magic experience
Secondly, you can pay two mana and tap it to double a target creatures power until the end of the turn