Custom materials created by Rhino when applying a material on a surface of a polysurface make the process less efficient. Architects and designers in general need a smoother experience—updating the app can help.
Having 15 materials but dealing with a list of 100 due to auto-generated custom materials is a major drawback. We should see only the materials used, not sift through a long list.
Think about a car or a building with many parts (polysurfaces). Dealing with over 100 unnecessary custom materials for just one model is a hassle. In reality, we might only use 10-15 materials in the entire 3D design.