You Can Sync Music To Apple Watch Without Your iPhone
According to Questions and Answers section on the Apple Music Membership Page, so long as you have an Apple Music membership, you’ll be able to sync music to an Apple Watch and play it back even without an iPhone nearby:
Does Apple Music work with Apple Watch?
With a membership to Apple Music, you can sync music to your Apple Watch and play it back — even when your paired iPhone is not nearby.
This suggests that it will be pretty easy to listen to music while out doing activities without needing to do any complex pairing or downloading of music to your Apple Watch. Given how annoying it is to do now, this is quite refreshing. Of course, with Apple opening the Watch to native apps, it’s possible that other competitors such as Spotify and Rdio may be able to do the same thing. Either way, this is great news and shows that the Watch is already capable of doing things without requiring the phone at all times.