Comment by TheOtherHobbes

On phones, most of the compute is used to render media files and games, and make pretty animated UIs.

The text content of a weather app is trivial compared to the UI.

Same with many web pages.

Desktop apps use local compute, but that's more a limitation of latency and network bandwidth than any fundamental need to keep things local.

Security and privacy also matter to some people. But not to most.