Personally, I'm a bit sceptical..
IIRC, "Wearable Computing" was developed over a decade ago now (no, not by Google), and, apart from specialist applications in military and exploration where it persists to this day, it faded away almost as fast as it appeared - simply because there was no demand for it. A "solution in search of a problem", you might say.
I was somewhat skeptical too... then I realised I make my living coding on some of those "wearable computers"
all the time - smart phones. For a long time, they too were "a solution in search of a problem"
... then Blackberry found a problem to solve, Nokia's N-series tried to muscle in on the game, and finally Apple convinced everyone else that life was not worth living if they were disconnected from the Interwebs for more than half an hour. There is more power & connectivity in the modern "wearable computer" we take for granted than in the first four of my desktop computers combined.
Do I think Google Glass is going to be the next iPhone? Nope. I do think, however, it is the next Blackberry. It will be useful for some, cool to have/use for others, and serve as the platform/inspiration for those that will take the idea to the next level.
As for being a chart plotter or similar... I don't think so just yet. The resolution of the display is too low and the device is WAY too expensive to be wearing on one's head at the back of the boar during heavy swell or chop. Give the technology some time to catch up to the promise of never having to pull the phone out to get/see information. It took a while for Blackberry's emails to become iPhone's... well, "everything there's an App for"
. It'll take at least that long for Glass to become as ubiquitous