It's an interesting situation with Clarkson. I mean, he is what he is - I don't think the issue is lack of effort, it's just that he's not all that talented. And it's not (entirely) his fault that he was signed to that big contract.
So what is the benefit to sitting him out in favor of Smith? Does Smith bring more to the team? I don't think so. So was the benching a way to send a message that results matter, regardless of contract status? If so, perhaps it would be more effective to have benched Kessel or Bozak or JVR. I know we won the game, but it was Edmonton. The Marlies might have been able to beat them.
I could see sitting him in order to give a young player a shot, or if he is about to be traded (one can dream, right?)...but not clear about the motivation here. Guess we'll know more after the next few games against better teams.