Beyond its unique back, the card featured a slightly different design to its Base Set equivalent, which is the most valuable Blastoise card
Most melded permanents are creatures and follow the exact same rules as any other, meaning you can protect them by giving them ward, hexproof, indestructible, or older mechanics like shroud
Because booster packs are randomized during production, duplicates may appear and completing a full set is not guaranteed from a single box
Selling graded cards or sealed product quickly at your expected price is harder than buying at retail
Some collectors may worry that the collection cards in their hands will not be as valuable as they used to be in the short term
It's fast, it's powerful, and it's consistent