I was using the standard iOS timer for a long time. I didn't like the noise knocking me out of my session. I built an app (https://quantifiedsit.com) that gently taps me on the wrist using the Apple Watch at the end of my planned session. That way I don't have to stop the timer.
I wouldn’t suggest that anybody needs a smart watch in order to meditate. I get a lot of value out of it myself. I enjoy keeping metrics such as heart rate and using reminders and tracking the time I’ve spent meditating. Your mileage may vary.
