I honestly can't think of a single way in which that's true, and he doesn't seem to provide any examples either.
Basically his point is that your phone comes with a camera, GPS, and persistent internet connection. Your desktop may have a webcam that is annoying to point around the room. The internet is fundamentally more useful when you have it all the time and the services you are using have an idea of where you are.
Maybe I really am a relic of the desktop era...
Cell connectivity and the ability to access internet anytime, almost anywhere trumps the limitations of a smaller form factor. And mobile device browsing speed keeps increasing every generation.