alt Hacker NewsiPhoto. iTunes. iCloud. iMovie. Notes.
None use the file system in anything like the way their unix underpinning would have files be understood or organised for users. Hard to even know where your files are without asking the app to deal with them one by one. Predated phones and even Spotlight doesn’t do a good job of showing/knowing where your files are.
And why should they? I don't know where my browser cache is either. Or my rows in my sqlite database. Or the system clock configuration. Actually I do know: They're stored on the hard drive.
Files aren't physical.