Yeah it could be used for that, though I'm not sure why Google Glass would be used in that situation. A chest strap to mount the device looking forward and maybe headphones in the blind user's ears (to speak out TTS directions, or even just tones which represent directions) would be a better feedback mechanism.
I agree. I suppose a Google Glass would be a bit silly since the screen would be unused, but seeing as it has most of the technology built in already, it would be easier to get a prototype working. An ear piece is another bonus added to the device as it could notify the user of obstacles.