Yes, quotation marks of some sort are useful. Even if they may be tricky to deal with from a software point if view.

Almost. I have found 2 or 3 uses in which my phone connected wristwatch gave me improved user experience. Most notable is a feature to buzz on my wrist when I leave Bluetooth range of my phone. Saved me from forgetting my phone numerous times. In addition, media controls (volume/seek/track) while playing audio with my phone not directly within reach is also nice. Last and not least - pressing a button on my watch to cause the phone to buzz or sound a tone is also useful. Both to find it when it's misplaced, and to override any game/media when my kids hog my phone... In those examples, it all comes down to a control device which is more likely to be physically on my person than my phone is. BTW, all these were experienced using a Pebble, not a crazily expensive, walled garden dwelling Apple device.

If you already suffer from an injury, I really think you want to avoid any additional risks... Ask an ergonomics expert. Most likely they would recommend a lightweight computer (to avoid shoulder injury on top), with some kind of external mouse. Maybe MS arc mouse as an example