[... ]does anyone own/use an Apple watch where their use case isn't fitness/health tracking? If so, what do you actually use your watch for? Is there any point in owning one if not for that?
1. It's a watch! With the always-on-display it works well as a watch. It can in some circumstances be harder to read than an analog watch. But the upside is that it works well in dark environments.
2. It is a way to find your phone quickly. If you don't remember where you put it, give it a ping and find it in seconds rather than minutes.
3. The notification relay means that it is much easier to leave your phone in your pocket, backpack or another room. If anything urgent comes up, you'll be notified.
4. As an extension of that, if you get a cellular model (my latest watch is cellular), you can walk as far as you want from your iPhone and still be reachable for an emergency phone call. This means you can go places without your phone.
5. Calendar widgets are super useful for work. In addition to telling the time, being able to constantly see my next appointment is useful. I don't have to constantly check my phone.
6. Checking your watch is more discrete than checking your phone. Being able to to see and quickly read notifications at a glance makes it easier to stay present and give the appearance of being present.
7. Apple Pay lets me pay in most (not all) stores using the watch. If you know where you are going, you can leave without your phone and your wallet.
8. Alarms. It is a convenient way to set short alarms for chores or cooking. There is also an alarm clock function that will wake you up without disturbing a partner.
9. Emergency flashlight. I think this might depend on the model, but mine has a fairly bright screen that may not light up a room, but is enough to find something in a completely dark space.
10. Even if you are not into fitness now, having historical health data is useful for finding a baseline and patterns. The trends can even help detect problems before you notice them yourselves.
11. Using watch faces and customising them can be fun. They work great with focus modes. I have one "regular" watch face, one for work and one for sleep mode.
As for downsides, in my opinion the biggest downside is the daily charging. I would recommend the Ultra for the larger battery. You still need to find a charging routine, if you are going to wear the watch at night.