Apple's Watch is designed to be both fashionable and functional.
A Webkit-based Platform?
By itself, this is just an interesting footnote for end users, however, a few other tidbits make for some interesting future possibilties.
With the introduction of Safari 3.1, Apple introduced a few Safari-specific features. This included CSS Animation and downloadable fonts. We've also heard that Apple demonstrated even more advanced browser-based 3D animation capabilities at WWDC. At WWDC, these features were demoed in the context of the iPhone, allowing developers to create CoverFlow-like functionality and animation within mobile Safari itself.
Another relevant feature is the recent adoption of client-side storage which allows web-applications to store data locally. This means that web-applications could be independent of an internet connection.
Developers and users alike may cringe at the thought of these poorly-adopted web features, since only Safari and web-kit based browsers are capable of supporting many of these features at this time.