Apple actually made clever use of the Apple Watch's relationship with the iPhone. Apple Watch users will install an Apple Watch app on their iPhone, which will be used to download apps onto the watch as well as likely manage Apple Watch settings. A user's iPhone is also used to help with computational demands. Apple cleverly pushes a lot of processor needs to the phone in order to preserve Apple Watch battery life. Thus, the Apple Watch is snappier, with longer battery life because a lot of tasks can be off-loaded to the host phone.
Smart way to handle Apple Watch apps for the first few generations until the Apple Watch can stand on its own. Reminiscent of how the iPod first required iTunes and a computer until it evolved into the iPhone and iTouch.