This mana generators value depends on whether or not you have enough legendaries to maximize its mana income
Encounter the mighty Chien-Pao ex, Ting-Lu ex, and other awe-inspiring Pokmonformidable creatures whose power is as wild as it is commanding
Kellan, the Fae-Blooded is another Boros equipment Commander
Whenever it or another Ally enters, you can essentially scry the top four cards of your library, and put any Ally cards you find back on top while the rest go to the bottom (although, you can choose to put Ally cards on the bottom as well if you don't reveal)
(You may cast cards from your graveyard for their escape cost.) If The Master of Keys is no longer on the battlefield when its second ability resolves, you'll still mill twice X cards
Most of the token stuff that generically good is quite high up the curve and so this is both a dead or low powered early card on top of situational late game card