(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
Compared to Thran Dynamo, this seems like a great fit for a lot of decks
However, if they get unlucky enough to land on tails twice, all they get to do the next turn is draw a card before the turn comes back to you
He does have a bunch of tags on him, including Villain and Pirate, so maybe that makes him somewhat relevant somehow
By purchasing Scarlet and Violet: Twilight Masquerade Pokemon TCG Live codes you can possibly acquire the following cards: Dragapult ex, Magcargo ex, Greninja ex, Luxray ex, Blissey ex, Sinistcha ex, Screaming Tail ex, Bloodmoon Ursaluna ex, Iron Thorns ex, Ogerpon ex, Carmine, Caretaker, Hassel, Kieran, Lanas Care, Enhanced Hammer, Lucky Helmet, Buddy Buddy Puffin, Rescue Board, Legacy Energy, Scoop Up Cyclone, Secret Box, Survival Brace, Unfair Stamp, Boomerang Energy
Just far too slow to be useful removal and far too low power when not killing things