While an interesting idea, I can't see this ever catching on. From the way it looks, it requires a lot of active use, meaning it's not good for on the go gaming where your killing time on a bus, back of a car, or in a waiting room or whatever. What's more very few people except nerds of the most extreme kind are going to walk around "ghost hunting" with a DSI. Your typical person is not going to stick themselves out or risk embarassing themselves by walking around like that. The video is showing the user wandering the streets in solitude with nobody around to notice them, that isn't reality.
Augemented Reality games are a cool idea, however I don't think human society (even in Japan) is at a place where this kind of thing is going to catch on.
I'd imagine when they really thought about it, this is why the backers pulled out of the project. I like the concept, but to me it seems mostly like it would be a tech demo as much as anything.
The similar cell phone games don't seem to involve quite as much activity as "Ghostwire" from what I've seen, and as a result it's less conspicuous [SP].
To sort of put a light at the end of the tunnel for those who like the idea, I will point out that as I was growing up "Co-Op" gaming was considered to be a bizzare concept and didn't have much of a following, despite the relative popularity of games like "Gauntlet". It wasn't until gaming, and society around it, evolved a bit that we started to see it becoming increasingly mainstream and acceptable. You see people playing co-op action games or rhythmn games all the time nowadays, even in public places. Way back when, working together on most video games was something of a anathema and seen as a bit wierd. Still given time we saw it move from games like "Double Dragon" and "Gauntlet" to a mainstream part of home gaming, and the Wii has even made it a social activity some "mundanes" enjoy.
In another decade or so gaming might seep into the public consciousness and progress enough where Augemented Reality games will become relatively mainstream, and then people will look back on ideas like this as "prototypes" for the idea.
While I'm a huge enough nerd (I mean truely massive) to try something like this, and even get some lulz out of people's likely reactions, I don't think even most of my nerdy brethren would do it at this point.
I vaguely remember years ago when they came up with the idea of releasing these handheld video games (like the Tiger portable things) that scanned bar codes on products, and created monsters based on them. The idea was that you were supposed to go around your house and whatever stores you had around, scan barcodes, collect the hiding monsters, and then pit them against the monsters being collected by other people with the same device in pokemon type battles.
You might go "I never heard of anything like that", and that is exactly my point. This idea is cooler, but also infinatly more intrusive. :P