In Unearth, the goal is to have enough points via die rolls on a card when a threshold is met to win the card. So higher rolls are generally better.
But, if you have poor luck, and roll below a 3, you get a little token that lets you buy other cards.
If you have the world's worst luck, and never roll above a 3, there's a good chance you can win the game through those other cards!
How else will he justify auctioning them off?