Vishgraz also ramps its power and toughness alongside your opponents' poison counters - something Phyrexians do very easily
The game has had its ups and downs with initial supply issues and a lot of speculative buying and selling that's since cooled off, but rare cards have remained a hot commodity
One of the best indications of this strategy can be found on the card Judge Magister Gabranth, which will become stronger each time you sacrifice a creature or artifact
However, as Insatiable Hemophage has deathtouch, I need only assign 1 damage to each of its blockers regardless of their toughness
Then you can discard two cards at the beginning of your first main phase to return this to your hand from your graveyard, which is card disadvantage naturally but with madness, lands, discard triggers like Archfiend of Ifnir, and loads more, it's got value