The massive cloud-based library of materials and textures added in the 4.x series significantly speeds up look-development.
If you are writing a piece on this specific version, here are the key "solid" points to hit: marmoset-toolbag-4-0-5-2-version-completa
A major highlight is the 3D painter. You can discuss how it allows artists to skip the "Substance-to-Marmoset" export-import loop by painting directly on the mesh. The massive cloud-based library of materials and textures
Toolbag is the industry standard for baking maps (normals, AO, etc.). Mention how the 4.0 updates made the "Bake Projects" more stable and faster. marmoset-toolbag-4-0-5-2-version-completa