No I don't think he should have been although he did all that was asked of him very well.
Folau and Cooper were more integral in breaking the Italian defense down.
Spiro gives a good description of the benefits of Cummins
The outanding Wallaby back was Nick Cummins, who set up a try and scored two himself. He presents defenders with the awful prospect of having to try to tackle a moving ensemble of elbows, knees and an angry, intense force that will not settle for anything but a do-or-die (for both parties in the collision) encounter with opponents.
Cummins is an example, often disregarded in Australian rugby (Rob Egerton in an early era is another similar type), of a player who gives 110 per cent in everything he does which makes him far more valuable to his side than more obviously talented players who perform below the level of their talents in hard matches.
http://www.theroar.com.au/2013/11/11/spiro-no-shroud-for-the-wallabies-against-italy-at-turin/
Is very rarely that I agree with Spiro, but here I think he is spot on