There are the printing costs (which I don't mind the team passing on to me because I'm able to sell my stubs for at least $.50 each).
The main upside for the team is controlling ticket resale. They can have an official "marketplace" that is the only resale option in town. They get all of the fees that Stubhub and EBAY are getting now (which I don't mind). What would not be good is if they set a floor on the price you can sell less popular games for (so you don't undercut the box office). And they could choose to really gig buyers or sellers on the fees since they have a monopoly.
Companies that have season tickets sometimes give every game to a different client. They are going to hate this too.