The rendergeometrysettings node has many artistic and technical uses and allows artists and TDs to add extra instance and prototype prim attributes to objects, scenes, lights, and collections, which can be found under the RenderMan tab

Just a few use cases are :

• Controlling Max Specular depth for glass objects
• Creating and defining trace sets
• Controlling the visibility of geometry or collections
• Defining Matte IDs
• Enabling Displacement on geometry
• Geometry render control
• Specific Motion Blur refinement
• Dicing
• Controlling volumes
• Polygon and subdivision control