I see a lot of people saying that the gunboats are trash, and, while they're arguably the worst of the unlockables in the update, and probably the least useful overall until they get a buff, the point of the war wasn't to introduce the gunboats alone. It was to get people excited for the Soldier and Demoman update overall--similar to what they did for the Spy update, by sinking it straight into the back of the Sniper update (...pun intended?). Basically, the way the updates were delivered sent waves through the Steam community, and the TF2 community, which is exactly what Valve wanted. They got popularity, they put their game up for free for a weekend, and more people boguht their game.
Also, IMO? The gunboats suck. But I support the war update.