Wearables only have 2 "killer applications", so far: notifications and fitness. To broaden their appeal they need to find others. I don't think that will happen this year.

The next likely killer application for wearables is probably automation, authentication and interaction with other devices. However the problem in this area is that the standards are too fragmented (AllJoyn, Homekit, Google's Brillo, etc) and the devices didn't reach critical mass, yet.

But you can be sure wearable devices won't fade away.