One of the biggest barriers to smartwatch adoption is the fact that, well, they don't do a whole lot, at least compared with mobile devices of comparable price. Sony has just bolted on a little extra functionality for their smartwatch line: the ability to remotely control shutters on various Sony cameras. The new Action Camera Extension app is free, and compatible with the original Sony Smartwatch, the Smartwatch 2, and the brand new SWR10 Smartband.
Install the app on your smartphone, and make sure you've already got your watch set up with Sony's proprietary Smart Connect app. If all goes well, the functionality should be automatically added to your watch: you can begin using the shutter button by using the Smart Connect app or activating it in your phone's notification shade. The watch app can control the shutter function, and on at least some cameras, start and stop video recording as well. On the Smartwatches, your watch's tiny display can function as a remote viewfinder.
Which cameras, exactly? Well, any WiFi camera that supports Sony's Camera Remote API. You can see the full list here. It looks like most of the GoPro-style Action Cam models are supported, as well as a few in the Alpha DSLR line and some of the NEX compact interchangeables. The DSC-QX10 and DSC-QX100 (those weird, clamp-on cameras meant to supplement smartphones) are also supported.
Note: we don't have the requisite watch and camera combo to test out the Action Camera Extension app, so we'll have to take Sony's word on all of the above.