In terms of units, Fitbit has probably been the most successful so far (22m units sold in 2016). They don't get attention in the US, but the Mi Band from Xiaomi isn't far behind.
I'd not heard of these glasses before, but for action sports they seem like the perfect fit. I kitesurf so I can't hold a camera, I tend to clamp a GoPro between my teeth to film. Same with surfers.
If these glasses had waterproof headphones I know tons of people who would snap them sup.
GoPro and third-party vendors sell a bunch of mounting accessories to put on your head or chest or wherever. Why don't you buy one of those instead of holding the camera in your teeth?
