Ah yes, issue 985. I remember that now. My conclusion remains. Adobe is part of the MWG. Through those guidelines, Adobe and the other members agreed that:
Description defines the textual description of a resource's content.
Also known as "user comment”, "caption”, "abstract” or "description”.
Exif ImageDescription, IPTC Caption, and XMP (dc:description) are mapped together.
This makes sense, as the words “description” and “title” are not synonyms. MWG Guidelines are silent on the “title” tag.