Attributes as used in the chapter articles are of a form atr/TEXT. This format should not be used for anything else, so as to enable attribute-searching via the general-purpose wiki search function.
Unlike tags, the absence of an attribute from a chapter article does not necessarily mean that the corresponding quality is missing from the corresponding chapter. Attributes are intended for use when someone inevitably decides to add an attr/Adorable to a handful of chapter articles -- they let users increase the specificity with which a chapter is described without the implied "You must re-read all of PMAS" associated with tags.
We're calling these attributes and the other things tags so that the people dealing with tags have a minutely simpler job on their hands.