Ok... I don't know how many people would actually need this but hear me out.
I was recently onboard a ship for 15 days with no internet access. No biggie. I am sure there is plenty of storage onboard the watch itself for two weeks of all day data and several indoor workouts.
It was interesting/frustrating that I could not see the workout since I could not sync. Why would I need to sync with Garmin to simply get the treadmill run from the watch to the phone and then being able to add pictures or make any edits I may need.
I also think it would be beneficial to be able to see all your activities even if they have not been sent to Garmin Connect.