I updated to a new version of Explore for Android (3.1). Then, after syncing watch and phone, all my beloved waypoints and tracks on the Instinct were completely GONE. Only after putting them into a collection on Explore AND updating the Instinct from 15.00 to 16.50 were they synced back from the phone to the watch. Explore was set to 'sync all' the whole time. Uncool experience.
Bottom line: There are people in this world who don't update firmware to the newest version automatically and don't sync everything to Garmin cloud, so think it very uncool when all their data is suddenly ONLY in one place, e.g. on their phone. Import and export of waypoints and tracks via Explore is mostly not working anyway, so unless you want to use USB all the time, this kind of almost-data-loss is not nice.
Thanks.