the Steelers won the ugliest super bowl ever. It culminated arguably the most impressive super bowl run EVER.
The only 6 seed ever to make it, much less win it. they beat the 1, 2, 3 seed in the playoffs, all on the road, and the #1 NFC seed in Superbowl, who had the highest scoring offense in the NFL and the League MVP.
They were 7-5 heading in to December. Had just lost to thier division rival, Cincy, at home. They Lost the division.
And proceeded to win the last 4 games of the regular season, which might as well had been play off games mind you (they had to beat Detroit at home the last game of the regular season just to get that last playoff spot!!!

, and then 3 playoff road games and the Superbowl.
add it all up....despite the perception of the game being boring or ugly yada, yada, yada, if you look at it for what it is as a whole, what the Steelers did was VERY impressive.
XL champs.