Typically, the more useful a card is, the higher the price will go for special printings
Players of more recent sets will see a few familiar faces like Gonti , Soaring Thought-Thief (theyre either Thief Acrobats or Arcane Tricksters), Thieves Guild Enforcer (yep, Xanathars got lots of hired muscle) and Zareth San
Most of the cards available at that mana value will send a creature from your graveyard to your hand instead, while Unearth returns it to the battlefield
Paying the full movement cost, especially on a lot of the more powerful locations, is just way too big of a tempo loss
It's even possible for it to be touching one of your creatures and one of your opponent's creatures, boosting your creature and damaging your opponent's
The set has had at least three print runs at this point, and my guess is that were getting close to the end of Unstable s shelf life