Maybe i'm out of touch, but is there actually a market for these kinds of things? I try to stay OFF my phone as much as possible, so at least for me, wearing a device on my face definitely doesn't have an appeal.
I already wear glasses, and if money weren't an issue (I'd expect the first ones will be
very spendy) and they weren't substantially heavier/bigger than my current glasses, and they worked really well, I'd love something like this. Not as a replacement for a phone screen, not something to have lit up all the time, but as something that can overlay data on top of reality
when I want it to. So, yeah, I'd be looking through clear glass most of the time. But I can imagine hundreds of scenarios where it'd be helpful. Beyond obvious things like walking directions that appear to be drawn on the ground in front of you.
Random scenario off the top of my head: you're anxiously awaiting the delivery of a package at home (and maybe you're not home right now). Your front door camera detects motion and evaluates it to be person-sized/shaped, The information gets passed along and a small unobtrusive "door" icon appears in one of the corners of your otherwise clear lenses (of glasses you'd be wearing anyway). If you notice the icon in your periphery and ignore it, it soon fades away. If, however, you stare intently at it for a second or two, one lens of your glasses overlays a half translucent feed from your front door camera - you can still see the world around you, but you can
also see your front porch. You see the delivery person walking walking away, and the package on the porch. You blink, and the overlaid image goes away. And now you know that the anticipated package is on your porch, and what it looks like, in real time, and you never had to touch anything - no taking out and waking up your iPhone, no raising your wrist to look at your Watch, etc. If you were walking around with things in your hands, you didn't have to juggle things around.
People seem to expect smart glasses to give you a super obtrusive all-singing all-dancing video game HUD all the time as you walk around. It doesn't have to be like that. It can be much more subtle, and be enormously useful. It's not that it's doing things that you cannot do, to some extent, with your iPhone, but then that was true for the Watch as well, and that has turned out to be quite popular (I love mine).