I think wearables will shine in a few key industries
"Businesses whose operations include high-risk activities or emergency services are strong candidates for wearables. Glasses containing instruction videos or documents become especially valuable to workers repairing bridges or oil rigs, as the Deloitte report notes. Ambulance drivers and firefighters benefit, too. They're never hands-off, yet they can look up anything they need, connect to hospitals and backup crews, and monitor their own health and safety. "
I think this is a good summary of where wearables will excel. Years ago there was a demo video done with a mechanic replacing engine parts using a heads up display on a wearable computer. The parts were all done with an overlay and he was given a step by step set of animated instructions. This type of application would remove a lot of human error or "best guess" methods of work. It would be incredibly useful for emergency personnel as well. Imagine firefighters going into a dark and smoky building with a HUD that overlays thermal imagery or building maps. Aside from that I know that I've had times that I wouldn't mind being able to remove a large monitor from my desk and exchange it for something like the Google Glass display.