Its the complete package, disruption dialed all the way up to a win condition
I feel for the developers making hours of content that people might never see, but there is just so much entertainment available to everyone that you can hardly blame people for not finding the time for all of it
Depending on what they agree on, it's also a great way to spice the game up a little bit
Meanwhile, the WIXOSS franchise's solution to this was to basically remake Yu-Gi-Oh!'s game and anime, but replace both the Monsters and characters with girls
If you discover an adventurer card, split card, or modal double-faced card, you might be able to cast that card with either set of characteristics depending on the effect's discover value
That'd be great on its own, but Ancient Cellarspawn also causes an opponent to lose life equal to the difference between the mana you spent and the mana you should have spent without all the discounts