This seems to me the obvious use-case for AR technology, but Hololens looks further along than Glass; I'd be interested to see where they have got with any comparable Hololens projects.
Hololens is really for AR, Glass is more for "HUD" type applications. Glass doesn't have a way to track the real world or align it with your view the way Hololens does.
Glass is basically just a tiny phone on your glasses.