There are no foils leading into/out-of the yellow areas. Ergo, they are (probably) not conductors! ;-)
[I find taking close-up photos always leaves me with less desirable results than I had hoped! No idea whether to blame it on the camera or the photographer! :< ]I suspect the carbon plated areas are preferred over copper foil perhaps due to the surface texture they impart?
Higher quality switches (of this style) would use gold contacts and a semi-metalized "rubber pad" (pill). It's always interesting to see where manufacturers spend their recurring dollars! Or not! :-/