From a detailed Apple Watch reality check; tangentially, see Apple, in Sign of Health Ambitions, Adds Medical Records Feature for iPhone (NYT)
"My recent Apple Store observation is not an isolated incident. More people are buying Apple Watches these days. During the three quarters leading up Apple's FY1Q18, Apple Watch unit sales have been up at least 50 percent year-over-year. From a unit sales perspective, this works out to Apple Watch sales trending at a little less than 20M units on an annual basis. In what will come as a surprise to most people, Apple Watch likely outsold Amazon Echo during the holidays despite Apple Watch selling for nearly 10x more money.Above Avalon: Apple Watch Is a Bridge to the Future
Based on unit sales, the Apple Watch business is currently about the size of the Mac business. When considering that the Apple Watch is less than three years old, for the product to be nearly outselling Mac on an annual basis is quite the achievement. As seen in the chart below, assuming Apple is able to maintain Apple Watch sales momentum, the sales gap between Apple Watch and iPad will continue to narrow."