There are many advantages of having the Apple Watch for me that make it quite indispensable at this point. The two biggest things for me is that I use it as a fitness tracker and notification machine.
I love being able to go without my phone on hikes/jogs/walks and just pair my bluetooth headphones to the Watch. It's a great way to remind me of my progress throughout the day, and as a daily encouragement to be active to fill up the rings. I like the addition of the Breathe app so I am reminded to just relax from the stresses of the day, and take in some deep breaths for my well being.
Now of course, I could just get a Fitbit to track my fitness, but it would not have the huge benefits of being a notification machine from my phone. I always have my phone on silent at work so as to not disturb my coworkers, but often will forget that it's still on silent when it doesn't need to be. I have missed so many notifications (ex. urgent emails) until later in the day because I'll miss the vibration from my phone. It doesn't help that the iPhone doesn't have a notification light so it's not like there's a visual cue if you happen to miss the notification. Having the Apple Watch allows me to always be on top of the notifications, and check my phone less for any updates; even a few of my coworkers noticed how much faster I was responding to emails and texts.
There are other advantages as well such as being able to tell what time it is without having to pull out your phone, and not having to be constantly tied to your phone. I also love the Maps feature where if you do navigation on your phone, your Watch will notify you of upcoming turns by having a unique tap for left and unique tap for right.
But in the end, the Apple Watch is really what you make of it, much like the iPad. If you find yourself not using the iPad at all, then obviously there isn't much of an "X factor" there. But if you happen to find uses for the iPad which make it really valuable to you, then it becomes much more of a must have to make your everyday life better. I have found my "X factor" for the Apple Watch. Maybe you'll find yours in the future.