The current Secret Lair drop, the ran-out-of-names Ultimate Pencil Superdrop, nothing is even tagged as low stock
But basically, its because each half is powerful all on its own
The obsession with serialised cards and The One Ring also sapped away some of the excitement, turning it into a lottery for people who dont care about Magic more than a new set to enjoy
But Nim Deathmantle (and cards like Angelic Renewal or Lifeline before it) push for a slightly different playstyle you protect your creature(s) already on board by reanimating them whenever they might die, punishing the opponent who removed them with a fresh round of triggers
Over the course of the game, you're going to be hopping across planes and seeing a wide variety of chaos effects
Pre-release and Draft Events Pre-release and draft events are excellent opportunities to build your collection and trade cards