Interesting. I got my Apple Watch last November, and by default, I think, it was configured to automatically update the OS overnight when the watch is attached to the charger. But, coincidentally, I changed that setting upon this current update. Now it just reminds me every morning that an update is waiting. The reminder is kind of annoying.

I tend to like to wait a while before installing new OS releases – mainly to see if there's any fallout.

(My watch never updated overnight because I never keep my watch on the charger overnight. In the morning I'd get a reminder anyway. I'd always manually update the OS.)