Walk the show floor at PAX Australia, or listen to any of the touring developers, and you'll hear a lot of chatter about games that are "good for PAX". It's basically shorthand for the kind of game that plays well on the show floor, but doesn't necessarily do well commercially. Couch co-op games often fall into this category: they're fun at a show, but that's it.
Unpacking is the opposite. It's singleplayer only. It's slow paced. It's not good for cycling a lot of players through a packed booth, and it doesn't compete for attention with loud visuals, sounds or mechanics. And yet, out of all the indies I saw at PAX Australia, it's easily got a better chance than most of being commercially successful.