I know it was applied to the bridge wings and similar high areas where crew had to stand long hours at duty, when on watch. It was to protect their feet from the cold steel of the decks. Wood was too heavy to apply to those areas. In lower areas wood was used. Apparently it was applied to many below deck areas out of sight of where you will be painting your models. But removed fairly early experience demonstrated that it burnt too well and the fumes were deadly….as well as dense. I think therefore you will find more on the early ships than later built ones.