I'm still trying to figure out why I'd ever need or want to use anything like this?
Snap photos of unknowing people, convince people you're taking photographs of them when you're not to drive them crazy, stalk random people you run into on Facebook, watch unclad photos of celebrities on your Glass while you're out with your significant other? So many good uses this device has.
But not to be totally dismissive, having a HUD device can be a convenience and could provide much facility and utility. They might be a presently useless (and disturbing) tool, but that doesn't mean it will stay that way forever. We will discover new uses, their capabilities improve and we will work on the problematic issues. More or less. Having an external source of visual information that follows your eyes is a step forward, and I like it. I can see them getting popular, but more importantly getting useful. It is a bit frightening, as I don't want people around me walking with cameras on their heads, but at one point their usefulness might outweigh the creepy factor.
What it will be actually used for I don't know. The future is unpredictable. Surgeons reading the manual during surgery? (We wouldn't want to disturb the patient.) Free solo climbing or BASE jumping groups sending live picture feeds to each other? (Finding sillier ways for people to kill themselves is always a nice endeavour.)
In all seriousness, it has already been shown to be of some use during surgery (for teleconsultation), and although I don't see how it is presently better than a head-mounted camera could be, having the additional visual cue of, say, patient's vitals might be helpful. There are also people who are deaf, and can't be healed with the help of an implant. Having a device that shows them the direction of sounds, warns them about loud ones, and does speech-to-text for them might be a great improvement, even if looking for a way to cure them would be money better spent. And I don't know what the guys at the transporter room in Abramsverse are using those for, but whatever it is, I am sure it is clever and handy.
And I can see myself using such one day. As long as it doesn't have fancy input using eye tracking, and instead relies on old-fashioned raised eyebrows, I'm fine with it.