The Apple Watch isn't designed to replace your iPhone just yet. In fact, it depends on it.
Many Apple Watch apps are really just displays for things running on your iPhone, and some key features aren't available if you aren't paired to an iOS device.
For example, the Watch doesn't have a GPS receiver, so if your phone isn't around you can't track the distance you've travelled beyond measuring steps.
And it doesn't have its own camera, so while you can use it as a viewfinder for your phone it doesn't have the ability to snap anything by itself.
That doesn't mean the Apple Watch is a dumb terminal, though. It has its own processor, sensors and on-board storage, and we're sure we'll see stacks of innovative apps as developers discover the possibilities.
We're already seeing some interesting applications, and the Watch isn't even out yet. Here are the key things you'll be able to do with an Apple Watch even when there's no iPhone for it to talk to.
Pay for stuff
Once you've set up Apple Pay via the Apple Watch app, you'll be able to use the Watch to pay for things in shops (or at least you will in America; at the time of writing Apple Pay has yet to launch in the rest of the world).
The app creates a unique token that's stored on the Watch to use as a card number. To pay, simply wave your watch at the Apple Pay-compatible terminal and let the built-in NFC (near-field communication) radio do its thing.
Get on planes or go to the movies
Apple's Passbook is on the Apple Watch, so anything already stored in it - aeroplane boarding passes, electronic tickets and anything else scannable - should work just fine without your iPhone.
It'd be nice to see more firms embrace this idea, because to date Passbook has been a big disappointment in the UK: we dreamed of binning our various loyalty, ID and membership cards in favour of electronic equivalents, but so far we're still wandering around with pockets and purses full of plastic.
Listen to music, audiobooks or podcasts
The Watch has its own storage space, of which 2GB is reportedly available for music - so you can use the Watch's built-in Bluetooth to pair with a pair of wireless headphones and get music on the move.
Naturally you won't be able to stream from the likes of Spotify without an internet connection, but 2GB is more than enough storage for a run, a workout or a short commute.
One of the smoothest features we saw at the Apple Watch launch event was SPG Keyless, a feature that enables Apple Watch users to unlock Starwood hotel rooms without anything as old-fashioned as a key.
According to Starwood, the keys work via Bluetooth Low Energy and are popped up by the iPhone app as push notifications the day before you check in.
The same idea could of course work with any other kind of Bluetooth-enabled smart lock, so it's possible we'll see Apple Watch-compatible locks for your home, garage or gym locker.
Track your fitness
The Apple Watch doesn't need to be paired with your phone to monitor your heart rate or workout: it can store that data and sync it to the Health app when you get back from your run, cycle or trip to the gym.
Control your Apple TV
Apple's Remote app has been ported to the Watch, and like its iOS sibling it enables you to control your Apple TV via the magic of wireless radio.
You can also use it to control iTunes and iTunes Radio on your computer, assuming you live in a place where iTunes Radio is actually available.
Do watch things
Hardly a surprise, this, but time-related functions such as the alarm, stopwatch and timer don't need a phone to function.
What iPhone-free features do you think we'll see from app developers? Let us know in the comments.