While some of these cards eventually appreciate as collectibles (especially if they have great art), the post-rotation dip can be significant and prolonged

100-card ready-to-play Warhammer 40,000 Commander DeckTyranid Swarm Green-Blue-Red Deckcontains 2 legendary traditional foil cards plus 98 nonfoil cards Every card features Warhammer-themed artincluding 42 cards that are new to Magic 1 foil-etched Display Commander 10 double-sided tokens, 1 life tracker, and 1 deck box The Ruinous Powers Commander (1) Creature (29) Aspiring Champion Be'lakor, the Dark Master Bloodcrusher of Khorne Bloodthirster Chaos Defiler Chaos Terminator Lord Dark Apostle Exalted Flamer of Tzeentch Great Unclean One Helbrute Herald of Slaanesh Heralds of Tzeentch Keeper of Secrets Khrn the Betrayer Knight Rampager Lord of Change Lucius the Eternal Magnus the Red Mortarion, Daemon Primarch Mutalith Vortex Beast Noise Marine Pink Horror Plague Drone Poxwalkers Seeker of Slaanesh Sloppity Bilepiper Tallyman of Nurgle Tzaangor Shaman Venomcrawler Instant (10) Bile Blight Bituminous Blast Blood for the Blood God

This deck relies on combat to win, and so having something that can mutate underneath a heavy hitter and draw you a card on combat damage, before getting copied with Krothuss to have even more of them doing the same, can be a game-changer
But they were also protected by it
Again, see the point above
S10A Dark Phantasma is the focused JPN release with 99 total cards (71 main + 28 secret) covering only Hisui-themed content