I guess I see your point, but the future is about seamless integration with all available technology (IMO). While you say smartwatches are owned by a small subset, my experience disagrees. Smartwatch affordability and sales increase show that it has become the norm is not a "small subset." I do think that there is an age discrepency with smartwatch ownership. When I fly, most of the guys under 40 at the airport has a smartwatch.
Now, is smartwatch integration with EFB something we NEED? I agree with you there, the answer is NO. It's a luxury. Hence, this is why I put it on the Wish List.
However, I think that eventually, smartwatch integration with EFB is something that becomes a norm in the future. I think it's safe to admit that Foreflight has and is still the gold standard when it comes to EFB related product development in aviation. The fact that they are integration smartwatches shows us that it is part of the future. Their current integration shows ground track, ETA, waypoint, METARs, altitude, flight timer (i think it is connect with the Foreflight app timer on the EFB), etc... You're right, we CAN get this on the tablet alone, but using/integrating all our smart technologies is the future (IMO). Imagine, when your watch starts to vibrate due to the fact that your oxygen saturation level is low in your blood when you pass a certain altitude and the alert is also sent to your tablet in flight. Your radar picture idea was pretty neat, btw. I can't believe I did not think of that. Combine that idea with some vibrating alert for extremely close proximity, would be awesome. Again, I agree, this is a luxury, not a NEED.
Unpopular Opinion - I do wish that AP would just focus its development on Android (Android guy bias). :D