It lets you risk milling yourself out, but can give you a whole host of board presence in the late game
By playing Little John, Resourceful Outlaw alongside the likes of Kida, Royal Warrior, Baloo, Von Bruinwald XII and The Prince, Never Gives Up, you can ensure that the character can quest for even more lore on its turn and takes less damage with the Resist plus one, which reduces the amount of damage the character takes by one
Upgradeability : Decks that can be upgraded into a currently viable competitive archetype more easily are ranked higher
Powerful staples like Lightning Bolt and Counterspell prove that some of the most valuable MTG commons are those that define entire strategies and see play in competitive formats
Add Lord Windgrace to a different Jund deck and we get what he adds without worrying about investing an entire deck into something we already have