Bennie Bracks, Zoologist is an Elf, but you're never going to try to build mono-White Elves with him as your commander
Its simply very hard to beat, and centralizes the metagame around ramping into this card
EDIT: After cinnaminhbun sold it I was able to buy it from the person he sold it to, so now that I have it in my possession, here a better picture than before: (Here a link to a side-by-side comparison with a Thick stamp.) One thing to note is that this non-Holo Thin stamp is not as Thin as a Thin Holo stamp
As a result, demand has far exceeded the current supply of Mox Opal on the market, and the card is skyrocketing
Another common mistake is not fully understanding or utilizing Trainer cards
Incorporate as of Alchemy: Murders at Karlov Manor is really an extension of perpetual, though a more brain-mushing one