It comes down early and powers out your key creatures then serves as a value engine later on when things get grindy
That said, it's not clear who put the item up for auction, or if it was even one of the original recipients
Rather, a second "reflexive" ability triggers when you sacrifice Eden, Seat of the Sanctum this way
There are 64 rares you can open in a booster pack, plus five themed rares available in Set Boosters, Theme Boosters, or Collector Boosters
Since you dont have to tap Ezuri to use this ability, you can dump all your extra mana into it, giving your Elves upwards of +9/+9 or more, and then take out your opponents in a single attack