The mythics in this color are more situational and toolbox-y than the mythics of other colors, which are often all purpose game breakers
Being able to discard your entire hand for two mana AND draw cards to replace it is a powerful enough effect that even more degenerate graveyard-based combos could be interested
While you control it, cards that are "decorated" (which the card uses to refer to cards with "premium" foil, alternate art or frames, and promo cards) have a miracle cost of one snow mana (which means that you can play the card for one snow mana if it's the first card you drew that turn)
A proxy on the other hand is plain and obvious about not being a genuine Magic Card
Venser also makes random other cards way stronger, like Nasty End sacrifice The Hollow to draw 3 cards for 2 mana, Vat of Rebirth gets loaded with oil as The Hollow dies, or Ringsight to give Venser skulk so we can bypass blockers while tutoring up a card