The smartwatch Conundrum: Simplicity at odds with complexity and size by Kevin C. Tofel on Medium:
“It’s like trying to cram today’s connected mobile experience into a flip phone from 1999. There’s only so much room to work with so you need to either have many “off-screen” items and expect buyers to swipe, swipe, swipe, or you can to clutter up the display with menus.”
Tofel’s assumption I think is off base. Of course fitting the functionality of a phone onto a small display would prove to be a terrible experience. Instead, what Apple appears to be aiming for is to decouple an app’s full experience from the small and frequent transactions the user has with it. Leave the full functionality to the phone and provide the user with the means to address a discrete action in its simplest possible form.
This is precisely how native apps displaced the web as the primary interaction model on the phone. Native apps distill the functionality the user wants from a given website into a more effective and appealing form.