Frankly I don't see any reason the watch can't be paired with the MacBook or iPad/iPod in the future. It's an understandable launch restriction, but in the end, there are plenty of people who don't own an iPhone but do own an iPad, iPod, or Mac. At a minimum, it would give people access to Pay, and likely serve as a way to sync the days calendar, reminders, etc. aside from notifications, I don't see the need to carry around the parent device all the time. Apple designed the watch to be autonomous.