It seems like the bent corners are merely an aesthetical touch added by the developer to add some authenticity to the TCG pack-opening experience you'd get in real life
Theyre not just for flavorthey give your opponent a leg up or slow down your plans, making every decision count
Not big as in popular, but big as in the monsters are absolutely massive

The mechanics include: Transforming Double-Faced Cards - cards that can transform into a different card Disturb - Cards that can be cast from a graveyard that transform into a different card Meld - Combine two cards into one more powerful card Emerge - Sacrifice a creature to reduce the casting cost of the Emerge creature Madness - Cast the card for its Madness cost when the card is discarded Escalate - A modal spell where you can pay extra for each mode beyond the first Flashback - Cast the spell from your graveyard for its Flashback cost Investigate - Create Clue tokens to draw a card Blood tokens - Create Blood tokens to discard a card, then draw a card Undying - Return the creature to the battlefield with a +1/+1 counter Miracle - Cast the card for its Miracle cost if it was the first card drawn this turn Soulbond - Pair two creatures together for additional abilities Thats a lot, and on top of all those mechanics, there are multiple versions of the transforming double-faced cards

That wedding does get violently interrupted, though, and it's all just a sham so that Yuna can attempt a magical dance that will send Seymour's soul to the afterlife (the plot of Final Fantasy X goes to some strange places)
When to Sell and When to Hold Deciding when to sell your Pokemon cards can take time and effort