Nice feature, specially for anxious people like me. I wash my hands a lot, but those 20 seconds seem eternal if you’re thinking about other things, talking to someone or in a rush. I’ll take this as a reminder of what wasting time is, that is, washing your hands quickly. Nice little convenience.
It is hard to train a IA to recognize sounds like those, so many sounds being made by different faucets and water pressures etc. So, putting it on the watch and making it available all the time, with that new pop up notification asking if you recently washed your hands, is a good way to train it and finish the mission of training the IA for the accessibility feature. How groundbreaking would it be for deaf people or the elderly to have Apple Glasses + Apple Watch in a future, and those notifications about important sounds right in your field of vision?