Phyrexian Arena Black Market Connections is a way better card, boomers, but I get why this is still played
It protects you from everything for a full turn cycle, then it becomes a card draw engine that scales with each activation
This is a case of pure collector-driven value
Kami can be tapped to add X mana of one color, where X is its power, and Troyan can be tapped for one blue and one green mana, provided its used toward an X-cost spell or a spell with a mana value of five or more
Most self-mill commanders reward you with some flavor of card advantage, so having one that generates power adds dimension to the archetype, and constructing your deck to maximize card types makes the deckbuilding interesting
For finishing up, Zeus Missing His Spark and Jasmine Soothing Princess are great