According to the visual guide it's got a heavy laser cannon (as opposed to the Stormtrooper transports "antipersonnel" gun), so it's got some firepower to bring to the table (or a cannon slot at least)
For those who think it doesn't have a place in a game ostensibly about space battles/dogfights - we have the Lambda class shuttle ... 'nuff said.
Lambda was a staple of many missions in x-wing and tie fighter, in those games you wouldn't want to joust them.