The biggest is that it just doesnt have the mana rocks you want to see in a Commander deck
With Phyrexian Rebirth youll be left with a creature of your own, and potentially a very powerful one

Other CGC-certified highlights pedigreed to the Jeff Ferreira collection in the auction include: a Blood of the Martyr (1994) The Dark, altered by Christopher Rush graded CGC 8 (lot 36040) a Plains (1998) French Ice Age Artist Proof, with a Black Lotus Drawn on Back graded CGC 8 (lot 36059) a Blank Card (1996) World Championship Decks, with a hand painted Black Lotus and heart graded CGC 7 (lot 36065) a Quartet of Phyrexian Negator (1999) Urza's Destiny Artist Proofs, with hand painted backs making a mosaic graded CGC 8 and CGC 8.5 (lot 36070) a Eureka, (1994) Legends graded CGC 9.5 (lot 37049) a Hell's Caretaker (1994) Legends graded CGC Pristine 10 (lot 37054) a Mirror Universe, (1994) Legends graded CGC 9.5 with sub-grades of 9.5 for Centering, 10 for Surface, 9.5 for Corners and 9.5 for Edges (lot 37058) a Ishan's Shade (1995) Homelands Artist Proof signed by Christopher Rush graded CGC 8.5 (lot 37120)

In Hearthstone, on the other hand, he's considered one of the most powerful and desirable cards in the whole game, since he has excellent value for his stats, is hard to cleanly remove and can easily go into almost any deck
They're all powerful and welcome ramp additions in a color that sorely needs them
The other big differences are the rest of the abilities that each equipment provides, but that's on a case by case basiseven two job select equipment can have wildly different abilities