Then you have to have the card graded by professionals, and since this has become such a popular trend recently, theres a huge backlog in that field, and it would take a long, long time to get that certification, whatever grade it ends up being
There are also many decks that make use of cards in the graveyard, like Mono-Green Food
Sealed Elite Trainer Boxes (all three art variants): original MSRP $40-45, current secondary market $150-300 each depending on artwork
The aftermath mechanic on Memory also makes it a prime target for flashback-granting creatures like Torrential Gearhulk and Scholar of the Lost Trove
Still, this doesn't mean I'm a fan of these products, nor that I'm looking forward to buying cards from these expansions