Sorry to bring up an old thread... but it's been a year now and smart watches are getting better.
In some ways they're frustrating — for example, I really wish mine had *seconds* on a digital watch face, is really that too much to ask?!
But overall they're great. For example it has the best stopwatch I've ever seen, with four completely different visual modes to display the same data, depending on the situation is.
I love being able to leave my phone at my desk while still being able to make and receive calls/text messages... those are a distraction during a show but they're oh so important in the couple of hours before the show starts. When someone's car breaks down and needs to be picked up, it's invaluable to receive that call immediately instead of being greeted by a voicemail whenever I happen to be at my desk next. And I like not having to check my phone regularly to see if there are any voicemails.
Once the show does start, simply flip the "do not disturb" switch and the distraction is gone. My pre-show procedure includes a reminder to do that.
When I work as crew, I like how mine (an Apple Watch) is available in an entirely black model, with no white writing or shiny silver or glow in the dark dots that would prevent me wearing a typical watch during a scene change. It even has a theatre mode where the screen stays off unless you tap the touchscreen with a finger. I like to run a stopwatch for the length of each act and take note of how many minutes into the show each of my tasks usually happen. When I have a break, I find it easier to relax if I can glance at my wrist and see how much longer I've got before needing to be in position.
I frequently use the voice assistant to take notes when I haven't got my pen and paper handy. Usually I just set a reminder to write something down later on.
I feel like there's a lot more I could use it for - there are smartphone apps for stage management but none for a watch that I’ve seen. And it seems like a smartwatch plus wireless headphones could be part of a perfect comm system. But even without those things it’s already indispensable to me.