Use your imagination. Here's the problem with most people: they aren't imaginative, they aren't creative, they aren't inventive. Highly intelligent people 'think differently' as the Apple motto goes. People of great intelligence have brought the world to what it is now. If Galileo didn't think differently, where would we be today? Newton, Edison, Tesla, Einstein... the list goes on. If Galileo didn't think differently from what everyone believed, the world would have continued to believe the Earth were the center of the galaxy, until someone did think differently. Just because you aren't aware of the plans, intentions, or future vision, or possibilities, doesn't mean there isn't one, and it doesn't mean the future of this product won't be groundbreaking.
I'll give you some possibilities and reasons for a wearable, specifically this watch, now and into the future, and this is just my random thoughts, I'm not being paid by Apple to sit around all day and come up with ideas, which im guessing Apple has numerous visionaries doing.
Some are obvious, some have been done and not mastered, some are obviously into the future. Ignoring the obvious things like notifications, timers, alarms, etc., just imagine the future biometric sensor possibilities. I know it's pretty much impossible to imagine some things which you wouldnt believe would ever be possible, but people are working on them. For example, there are people working on a slew of biometric sensors that can give information non-invasively from the wrist. Glucometers (I know most people don't understand how this can benefit anyone but diabetics, but in fact it can benefit every human on the planet, as blood glucose is incredibly important and can tell a huge amount about a person's health, possible future complications like type II diabetes, insulin resistance, etc. and learning how the foods you're consuming are negatively affecting your blood glucose levels, could get people to eat more healthy, as opposed to carb-laden, highly refined, processed garbage), blood pressure, oxygen saturation, electrolyte levels, and even calorie consumption (yes in the future it could be possible for your watch to tell you how many calories you've consumed) broken down into the specific macronutrients, all non-invasively. I've even heard further down the road, maybe 20-30 years it may be possible to detect cancer cells non-invasively from a watch's sensors, looking into your blood (detection of one of the first thousands or tens of thousands of cancerous cells as opposed to the first tens of millions, and early detection like this could decrease mortality substantially). Those are just some of the possibilities with biometric sensors. The key thing to remember here is that non of that is possible without it being wore as in a watch, because of the inherent nature of it always being worn on the body, to monitor constantly.
Another key thing I like to think of as on Apple's future roadmap as a feature is an aura of security. The inherent nature of the device always being attached to your body brings about the unique opportunity to make it be your virtual key to everything you own, around you. Being that it has sensors you will be able to authenticate it each time you put it on your wrist, and through its sensors it will know that it is remaining on your wrist, and thus, remaining authenticated. So all of your devices lock and unlock based on your proximity to them; you walk up to your Mac and it doesn't need any password or authentication because it did that as you entered the proximity of it, and as you walk away it is locked as if it broke out of your aura of security and thus is no longer authenticated. Another example... you walk up to your house the door will unlock as you approach it, and when you leave your house the door could lock after you exit the proximity of a few feet. Same goes with your car, and it could act as a key fob by giving you a certain haptic feedback as you walk away so you know it's locked, as well as an audio cue. With numerous other applications for automated things in your house. For example if you are sleeping with the watch on while its monitoring your sleep, and you get up to use the bathroom, it could turn the lights on dimly without you doing a single thing other than getting up and walking, because the sensors know you've gotten up. In the future when there are more sensors, it could give you strong, repeated haptic feedback to wake you if the sensors determined you were starting to fall asleep while driving.
Then you bring in more complexity like gestures (and this has been done on a wrist device already), you walk up to the trunk of your car and simply do nothing but raise your wrist and the trunk unlocks and pops open (aura of security and gestures all accomplished by the sensors), and the same goes for the hood. Numerous other possibilities with gestures too.
These are just some of the myriad of things Apple plans for this product down the road, I think. What everyone needs to remember is that you know virtually nothing in regards to what Apple is working on, considering, or planning. They've been working on the watch for over 3 years, their plans are far-reaching. Sorry for the lengthy post.
