The thing that makes Garbutt valuable is that he seems to be able to generate shot attempts on the opposition net (which when you think about it requires you to have possession of the puck in the opposition zone) at a rate that is almost uniquely good for players that are on the ice for 11-13 minutes a night (I'll use that description instead of 3rd / 4th liner). Antoine Roussel seems to share this quality with Garbutt, and the two have combined to form a very effective two way line no matter who they are centered by.
Usually these guys get trapped in their own end and give up scoring chances by the boatload if top players on the other team are up against them, Garbutt and Roussel are able to not only prevent that from happening to them but often push back. If you have guys like this lower down in the lineup it goes a long way towards giving your top players a break from shouldering all the responsibility for creating attacking zone time and chances. We all saw how terrible Pittsburgh looked last week when the best they can ask from their depth players is "please don't screw up too badly when you are out there and allow a goal".
