[basseq]

As a file format, sure, it's robust. Garbage-in-garbage-out, though. A directory structure would be just as messy, and harder to use.

And great point on export. Assets like pictures are an example: you'd still need to store them somewhere. (IIRC, GEDCOM format points to a file path of some sort.)

Edit: actually, you can embed multimedia (as a BLOB of some sort) directly into a GEDCOM, but I'd leave the files separate to maintain human readability.