Because of the rich history of the Pittsburgh Steelers in the Super Bowl, one can actually make predictions based on previous appearances. In the first six Super Bowls, the Steelers played the Cowboys three times. Let's ignore those and look at the other three.
In all three games, the Steelers were the favorite. In all three games, the Steelers played well, but not perfect. In all three games, the opponent showed toughness and gave a real good showing. And in all three games, the Steelers scored late to cement the game and win by double digits.
I see no reason why the game won't follow this script.
Steelers 27, Cardinals 16