There was a time when a phone was the size of a brick (and just as heavy) and all you could do with it was to make and receive calls. Later a flashlight was added, then a calculator, and some games. Remember Snake? I was a champion at it.
Then there was texting, the alarm clock and an ever growing number of other features, so pretty soon when you left the house you would only need your phone: no more notepads, pens, calendars, cameras, stopwatches, and even your wallet became optional.
Phones got thinner and smarter and changed their names to smartphones.
And after all the work of incorporating everything in them, a new trend came along and tech manufactures and designers decided to take apart some features and reinvent them as separate devices — smaller, easier to wear and of course, even smarter than the average smartphone. These devices are serving a bigger purpose.