Yes, it's just a fad for now, because it's too expensive and awkward to be anything else.

And at best I think it will become a niche platform that has some limited uses, but it will never become ubiquitous like in science fiction. The fact is there are simply too many applications for which existing input methods (keyboard, mouse, etc) are better suited, and to which simulated visual and audio immersion don't add much value.

Between the two, though, I think AR will find more uses.