I think a lot of the side metals could have other uses since many times materials like pure zinc or bismuth get relegated to lantern fodder, decorative blocks (sometimes), or dye. It's considered a waste to not alloy those materials, which stinks since I have been finding a ton of bismuth deposits near where I am. At bare minimum, brass has a special use making torch sconces.
That aside, I will say that the sphalerite(zinc) ore texture may need some reworks. The texture is almost indistinguishable from the rock it's inside and I think that contributes to the problems with locating it.