Any good argument that anyone can think of for a scenario where smart eyewear will not be as ubiquitous as smart phones eventually? I understand the privacy argument, but that is not going to be enough. The ability to think or blink in a certain way and capture anything you see is too powerful a tool, alongside the augmented reality that is coming.
The reason I do not wear a smart watch is not because they're not useful, but because it's simply not comfortable for me to be wearing something on my wrist. It's not a big deal, but I prefer to not wear rings, watches, bracelets, etc.
Similarly, I prefer contacts over glasses because of a 1) glasses reduce your field of view / quality of vision, 2) the touch / feel of having something on my face, and 3) them inevitably falling off or being grabbed by my baby.
Smart watches got as ubiquitous as normal watches, and smartphones got as ubiquitous as wallets (and other things you might keep in a pocket or purse). I expect smart glasses will become about as ubiquitous as regular glasses.