Many such cards have a triggered ability that transforms the card (when it's on the battlefield.) One of the most typical such ability is " at the beginning of each upkeep, if no spells were cast last turn, transform (this card) ." Many players actually don't realize that this is a normal triggered ability that uses the stack, and therefore can be responded to
You'll get loads of boosters from multiple editions, stock up on energy, expand your card sleeve collection, get game-critical tags, and learn how to play and build a deck
This effect should be crisp and uniform across the entire card
You really don't need much more than a few card boxes to keep this bulk tidy, though
It's this scarcity that makes them so highly desirable though, with some players using them to flex their incredible luck (or, in a lot of cases, the thickness of their wallets)