Apple's Watch is designed to be both fashionable and functional.
iPod or iPhone Media Remote Control
A portable multimedia player (such as the iPod. manufactured by Apple Computer, Inc. of Cupertino, Calif.) is used to wirelessly access and control a media server (such as a personal computer running iTunes software) that is streaming digital media by way of a wireless interface to a media unit (such as a stereo/speakers in the case of streaming digital audio).
Unique to the devices would be the ability to transfer digital media file metadata - such as song title, author, etc. associated with the music or video.
The patent application was filed in 2005, so represents technology that Apple was working on a couple of years ago.