Not to be pedantic here, but Gray really isn't all that creative.
He's only just overtaken Digne for us on chances created, despite having played seven more games
He's not a creative winger at all. He basically gets the ball and has one thought which is attack the goal/box and occasionally he puts a decent cross in.
So what a player like VVB, or Alli, if coached right, offers is an extra threat to take a defender away from Gray. Villa marked him out of the game the other day by constantly doubling up on him.