To date(26.10.2023), there are 118 materials in the collection.

From my own experience after 2 years of daily work in the international office as an Archviz Architect in Blender. I think that in daily routine you don't want to have a "closed" Node Grouped Collection, where you can get access to only to a few components. You need to see the whole situation quickly and in most cases - change or create the direct component. For a faster and more understandable workflow. I would prefer to have my materials "open" without Group Node. When I wanted to learn to create materials, I didn't want to edit only specific properties, I wanted to see, change, and especially understand, what is going on. That´s why are this collection different from most of the libraries. 

Yes 100%. Any update with new materials will be part of the downloadable files for anybody, who has got older version.