Specular maps are used to determine what parts of a texture shine more or less light. This creates variations in surface material, EG: a metal grating can have highlights on raised surfaces while recessed surfaces will be duller. In materials lighting, Asobo was getting the specular luminance value to determine how things would chrome or clear-coat, and they went all-in on it. But, I modified it to let the specular phase into the underlying texture better, and let some of the underlying texture show through. This lets the underlying texture add variation to the chrome and clear-coat. In the image above, we can see how the once fully-chromed (looked brand new) tanker trailer is now a weathered wreck. The chroming has faded and oxidized in certain places. This is the blending of the chrome'ing reflective map giving way to the underlying weathered texture.
Specular maps are used to determine what parts of a texture shine more or less light. This creates variations in surface material, EG: a metal grating can have highlights on raised surfaces while recessed surfaces will be duller. In materials lighting, Asobo was getting the specular luminance value to determine how things would chrome or clear-coat, and they went all-in on it. But, I modified it to let the specular phase into the underlying texture better, and let some of the underlying texture show through. This lets the underlying texture add variation to the chrome and clear-coat. In the image above, we can see how the once fully-chromed (looked brand new) tanker trailer is now a weathered wreck. The chroming has faded and oxidized in certain places. This is the blending of the chrome'ing reflective map giving way to the underlying weathered texture.