In terms of winning, it allows the Flyers cap space to keep Claude Giroux up. That will help the team. Upshall became expandable with Giroux around. And Carcillo can fill Upshall's role but you'll have the addition of Giroux being able to stay up, now that Briere is back.
Carcillo can play and has some upside. He averaged a point a game in Jr while racking up PIMs.
Carcillo is like Darcy Tucker - a tough player with some skills.
And honestly, I think the Flyers aren't good enough to contend for the Cup anyway. They are still need another solid defensemen, preferably one who can move the puck.