It also has flying and only needs a single creature to crew it, so its super reliable
Crucible of Worlds plus an additional land drop plus a way to mill yourself puts so many necessary effects into a single card that its hard to beat
If such an ability requires a target, you can target a Room even if both of its doors are locked, but the ability won't do anything when it resolves
The issue, then, is not as much justifying playing Boseiju in those decks, but rather featuring it in a Cube at all

Here are the top five pulls from Trick or Trade: Gengar 57/091 Cosmos Holo Darkness / 130 HP / Stage 2 Ability: Night Gate Switch your Active with a Benched Pokmon once per turn Nightmare (100): Opponents Active Pokmon is now Asleep Weakness: Fx2 | Retreat: 1 Current Price: $5.76 Market Price: $4.86 Launch Price: $0.31 Munkidori 095/167 Cosmos Holo Psychic / 110 HP / Basic Ability: Adrena-Brain If this Pokmon has D Energy, move up to 3 damage counters from 1 of your Pokmon to 1 of your opponents Pokmon Mind Bend (60): Opponents Active is now Confused Weakness: Dx2 | Resistance: F-30 | Retreat: 1 Current Price: $2.31 Market Price: $1 Launch Price: $0.23 Pikachu 018/091 Cosmos Holo Lightning / 70 HP / Basic Growl: Opponents next attacks do -20 damage Pika Bolt (30) Weakness: Fx2 | Retreat: 1 Current Price: $1.81 Market Price: $0.50 Launch Price: $0.14 Mimikyu 037/091 Cosmos Holo Psychic / 70 HP / Basic Ability: Safeguard Prevent all damage from Pokmon ex and Pokmon V Ghost Eye: Put 7 damage counters on opponents Active Weakness: Mx2 | Retreat: 1 Current Price: $1.56 Market Price: $0.27 Launch Price: $0.28 Darkrai 136/197 Cosmos Holo Darkness / 130 HP / Basic Dark Slumber (20): Opponents Active is now Asleep Night Cyclone (120): Move all Energy to your Benched Pokmon Weakness: Gx2 | Retreat: 2 Current Price: $1.52 Market Price: $0.26 Launch Price: $0.14 The values may not be sky-high, but thats not the point of Trick or Trade

Mind Stone Mind Stone is an easy-to-include mana rock in your EDH decks because you get a mana and later cash in for a card