I disagree; this wristband might be a game changer because your hand does not need to be free to use it (at least in theory, we'll see how it actually plays out). Also, I'm willing to bet that for some people, this wristband might be more accessible than a regular keyboard (i.e. people with limited mobility or missing hands). Compare it to the laser beam keyboard, which is just a flat version of a regular keyboard.

> why have mechanical keyboards become so damn popular and not "keyboards on screens?"

Keyboards in general have become more popular, as more and more people get computing devices. I'm willing to bet the increase of keyboards on screens is much greater than the increase of mechanical keyboards; there are far more smartphones than mechanical keyboards.