Use average user as excuse for not implementing the feature is laughable. Most modern OS has protection mechanism that protect most important system files. Average users will not and would not choose to mess around with system files anyway.
Having use File managers on Android devices really make it easy to managing files and sharing files around with different application. There is no more uploading files to Dropbox, then open files by different apps through Dropbox's share sheet. Just need download the file from internet or drag and drop. Easy.
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The current implementation is not better and not more efficient than a decades old concepts. Most of users are grown up with full featured file managers, regardless is Windows a Explorer or Finder. Having a file explorer made it really easy to manipulating files,