When you look only at Romo's sacks and compare them to incompletions, obviously the incompletion is the preferred option. But when you look at every one of Romo's drop backs (not just the sacks), and compare them to every other quarterback's drop backs in the playoffs, you can see the decided advantage of his performance over those of the other QB.
Adjusted net yards per attempt looks at all drop backs (completions, incompletions, interceptions, throwaways, and sacks). Here is how Romo compared to all other playoff QB.
pass yards - sack yards + (20 x TD) - (45 x INT) / (attempts + sacks)
Romo 8.2
Flacco 7.6
Brady 6.9
Rodgers 6.4
Stafford 6.3
Wilson 5.7
Newton 5.3
Luck 5.3
Manning 4.6
Rthlsbrgr 4.1
Lindley -0.9
Dalton 3.8
If you don't think ANY/A has anything to do with winning football games, just know that passer rating has the highest win correlation of any major individual stat. One of the criticisms of passer rating is that it doesn't include sacks and sack yardage. Well, ANY/A does. It isn't talked about as much as passer rating, and it's hard sometimes to find the data without really digging. Although regular-season ANY/A can be found at PFR, I had to do my own work for the playoff ANY/A.
This study looked at 22 NFL seasons and found ANY/A to have a slightly higher correlation to wins than even passer rating.
Adam's version of the above stat does not include touchdowns, going by the theory that passing touchdowns are worth no more than the yards it takes to get them. Here's ANY/A without TD for this year's playoffs:
Romo 6.9
Flacco 6.0
Stafford 5.8
Brady 5.5
Rodgers 5.3
Luck 4.8
Wilson 4.3
Manning 4.2
Rthlsbrgr 3.7
Dalton 3.8
Newton 2.7
Lindley -1.4
Looks like Romo knows what he's doing.