A card's presence in The List does not make it legal in the Standard format, however
Every card shows its current market value so you never miss a deal
The deck also fully takes advantage of having access to blue/green and has an impressive "out of the box" ramp and card draw package that helps it quickly get up to speed and stay in the race as the game goes on
It can effectively shut down graveyard strategies in any format, from the Dredge deck of Modern to reanimator commanders such as Sedris, the Traitor King or Meren of Clan Nel Toth (and it can be cast for free in the opening hand)
While this was partly because people simply assumed Dredge couldn't work without the banned cards (without Dread Return, the Bridge from Below combo doesn't work, and without the combo, traditional Dredge was off the table in Modern), it's also that the deck was simply lurking behind the scenes, waiting for the right pieces to be printed