First off, thanks so much for the support and assistance in understanding the work being done here. Thanks to those editors who restored the wholesale deletion of the catalog property.
Secondly: While the Black Lunch Table is unique in both its scope and outreach, other projects are using the category in actual "real-world things." They are not internal WikiProjects.
An example of this is the GLAM project for Colección Patricia Phelps de Cisneros (CPPC). CPPC is a large and active private Latin American art collection that is improving coverage of Latin American artists on the projects, with the intention of adding at minimum articles in English, Spanish, and Portuguese. Which is why Wikidata is so helpful, for it's language neutral interchangeability of the scaffolding of metadata and the establishment of notability via VIAF and other identifiers.
The CPPC GLAM project has multiple task lists and SPARQL queries in Listeria tables. CPPC also plans on doing an image donation to the Commons in the next 6-12 months as the project develops and as full metadata is collected and implemented in the most robust Wikidata-centric way. But first the publications and artist metadata needed to be populated.