This is not true. Hololens is untethered and there's nothing preventing you from using it anywhere. Well, nothing except the fact that it's bulkier and heavier than Glass and obscures your face too much for use in social situations.

The real reason why AR isn't better than Glass for this kind of thing is that AR tracking and recognition of objects is not good enough for real applications yet. On Glass as reported in the article you have to scan a code to identify an object you're holding. In people's imaginations, an AR device would magically recognize the object and overlay useful informational displays on it as you turn it in your hands. In reality Hololens is not even close to being able to do this, so you would be reduced to scanning codes just like on Glass.