If you are writing a piece on this specific version, here are the key "solid" points to hit:
The massive cloud-based library of materials and textures added in the 4.x series significantly speeds up look-development. marmoset-toolbag-4-0-5-2-version-completa
This version cemented Toolbag's shift toward a high-end, GPU-accelerated ray tracing engine, making it a rival to offline renderers for portfolio work. If you are writing a piece on this