This is actually an interesting assessment for me, since smartphones are pretty much the exact opposite (can't even see the filesystem on some of them): There's only apps, and the apps have stuff in them. Sure there's ways of exchanging data between apps, but documents/files aren't really a thing.

Conceptually, that means I feel like I'm using services/tools to interact with this abstract 'data.' By keeping 'data' abstract, it feels less solid who owns it, who's responsible for it, and where it is. Now I'm interested in the opposite system where the 'documents' are the core concept of the device, and programs are just "things your computer/smartphone can do with this document." Really make the data feel like it's /there/ you know?