In an effort to reduce dependency on any one product, I would like the ability to force the export of sidecar files for ALL formats in a referenced library.  I see sidecars as having several advantages: 

1.  Suitably parsed in a script, it can be used to drive a tool such as exiftool to update meta-data in jpegs.  (Many editors mangle or only write incomplete metadata to derivative images.

2.  Belt and suspenders:  If the database crashes, you have a source for rebuilding your database metadata in what ever application you are using.

3. If you are using cloud storage, writing a few kilobyte sidecar file is much faster than a modified image.