Reducing the cost on this is super doable even outside of graveyard decks, and it's a pretty scary threat when it comes down for 6 or so mana
You technically could use them for a graded slab however, since these are a bit thinner, they're not very stable
The third proxy is by Developer C, and it is a thing of beauty
To conclude, while there is nothing remarkable about the card rarities in this set, this is further proof that a lot can be learned from looking analyzing the uncut sheets
P/T Number 62 Language English Legal Formats Commander, Legacy, Modern, Pioneer, Vintage Not Legal Formats Alchemy, Brawl, Competitive Brawl, Historic, Pauper, Standard, Timeless Rulings (4/15/2013) The last ability can't reduce the colored mana requirement of a spell