There's been a lot of print variance over the years, and when you add in special printings like Challenger Decks reusing the same set symbols for cards produced by different printers at different times, or cards printed in other regions, there are often subtle but noticeable differences between legitimate identical cards
Back in the days, people played without sleeves and many of these old cards weren't stored properly
It makes it far more expensive to pick up the individual packs, coming as they do either with frippery and extras like coins, oversized cards, or sleeves, that bulk up both the contents and the price, or in individual booster packs at $5 a pop
It's not the most fun to resolve or play against, and the games where it is cast are rather silly
New cards will be found, expanding on growing list of abilities that was introduced in Shards of Alara
If a source would deal damage to a player or battle this turn, it deals that much damage plus 2 instead