I used the watch for medication reminders this week while sleeping. I use haptic with sound off, and the alarms tap continuously on your wrist. It would wake some people, unless you are a very heavy sleeper. Even then, I expect continued tapping on your wrist would eventually bug you and you would wake up. Try it sometime with the watch timer and see what happens.
Snoring is a symptom of Sleep Apnea. Not all snorers have Sleep Apnea though. Sleep Apnea can cause a range of issues that can lead to morning death. Other symptoms include high blood pressure, high cholesterol, sleepiness during the day, depression, and cardiovascular disease. Edit: It impacts all types of people: Thin, overweight, obese; it doesn't matter. Losing weight does relieve the symptoms but you'll still have sleep apnea. You only have sleep apnea when you're sleeping not when you're awake. It's very hard to detect on your own. Snoring is a key indicator.