The only issue was that the mechanic referred to outside the game
This is rarely relevant for the proactive decks as they typically have few groups of cards and one, perhaps two major groups other than land
You may reveal a creature or land card from among them and put it into your hand
Naturally, Games Workshop wasn't gonna let Wizards play with its toys unless they laid down the lore first, and Warhammer Community assures the crossover "involved substantial input from the Warhammer 40,000 design studio, ensuring every last detail matched the Warhammer hobby you know and love
Unstable booster boxes are much more affordable given the set is not as oldthey sell for somewhere in the $150 range
The card advantage, while also filling the grave with Knights you can recur later, is flawless