With Handoff you can push not just data but state between iPhone, iPad, and Mac. Imagine having that for iTunes... and for Apple TV?
This is my beautiful iOS 10 media dream: Start binge watching The Expanse on my Apple TV at night, get tired, get up and walk to my room, swipe up on the Video icon on my iPad lock screen, and keep right on watching. Get in the zone with an amazing Apple Music playlist while I'm working on my Mac, go to grab some lunch, swipe up on the Music icon on my iPhone and keep right on listening.
Handoff is part of the Continuity features Apple introduced in 2014. It lets you move seamlessly from iPhone to iPad to Mac and back again. You can start an email on your iPhone and then switch to Mac to really pound it out. You can prep a Keynote on your Mac and then make last-minute adjustments on your iPad right before the pitch. You can even start a call on your Apple Watch and complete it on your iPhone. For messaging, browsing, document editing, and more, it's ludicrously great. As long as you're logged into the same Apple ID, and in proximity, everything you do can be started, continued, or finished on all of your devices.
Handoff currently doesn't work with anything iTunes — music, movies, TV shows, etc. — or with the Apple TV.
Though Handoff shipped in 2014, Apple bought Beats in 2015 and my guess is that — and the new Apple Music service that followed — complicated matters. Figuring out how to bring the past into the future is no easy task.
I'd love to be able to start a playlist on my Mac and then walk away, pick up my iPhone, swipe, and keep right on listening.
The technology all seems to be in place, though. Continuity works by using Bluetooth LE to broadcast activities, then activates the internet, iCloud, or direct peer-to-peer Wi-Fi transfer to make that activity's content available on other devices to continue those activities. So, iMore for Safari on the Mac would trigger Safari for iPhone to load iMore as well. Keynote on iPad would cause Keynote on your Mac to check for the current file in iCloud Drive and, if so, grab it. A half-composed Mail message on the iPhone might push the content of that Mail message right to the iPad.
Doing peer-to-peer Wi-Fi transfer is okay with small files. Trying to push a 1.3 GB TV show file or 3-4 GB movie file, however, is an entirely different matter. That why I've kept this constrained to iTunes and not talked about audio and video files in general.
iTunes content is kept on iCloud's servers: That's' how we're able to re-download music, movies, and TV shows we've already purchased. It's also how Apple Music can just start playing almost any song any time you ask for it.
So, extending Handoff to iTunes could take advantage of the existing systems. Apple ID would make sure who is involved in the transaction and that they're authorized. Bluetooth LE would take care of proximity and broadcast that you're listening or watching, what you're listening or watching, and where you are in the timeline. Pick up another device, and that request goes to Apple's servers, finds the iTunes content, and starts streaming from exactly that point.
We've already gotten the next generation Apple Music service and the new Apple TV. All we need now is Handoff to tie it all together.
Because Netflix and other streaming services work in a similarly cloud-centric way, my guess is they could work in a similar way for Handoff as well. You can already open the Netflix app on any device, find the show you were watching, and resume it. Handoff would just make the process faster — you wouldn't have to open the app and find the show, you'd just swipe or tap and keep watching.
Continuity, like extensibility and on-demand, is transformative. It unbundles apps, letting their discreet functionality come to where ever you are. It decouples the interface and changes it from pull to push. It's going to change the way we use our devices.
We've filed a feature request for Handoff for iTunes with Apple: rdar://25024354. Dupes appreciated. Also comments below if it's also a feature you'd like to see!