MetaData is already built-in to most modern file systems. On OSX (HFS Plus) you have the xattr command, and there are things for ext2, ext3, XFS, ReiserFS...
Sure, but it’s neither portable across platforms, nor user friendly (for non-techies).
Imagine managing a collection of photos (or a mixed collection of multiple file formats, like scans of receipts, and pdfs with invoices) in something like Dropbox: no access to hidden low-level metadata blocks, etc., let alone easy editing. Not to speak of cross-platform support.
File names are always visible and editable, and they’re easily parsable.
