Not just that. We have a lot more metadata these days and not everything can be a file. If you keep all the metadata and database-like files accessible to the u

Not just that. We have a lot more metadata these days and not everything can be a file. If you keep all the metadata and database-like files accessible to the user, how do you handle store corruption? EG, a video recording/playback app that allows the user to save bookmarks/timestamps. You'd need to have some place to store those bookmarks, extract frames, generate multiple resolutions for both the video and frames (for gallery previews etc), possibly add some more metadata... It's much easier to hide the actual files from the user and give them the option to export the data in some user-readable format. Apple is notorious for this. Everything is a soup of folders and files with hashes and .plist files. Similar story with iOS and Android.