We don’t just use gold for jewellery because it’s valuable, we also use it for that because it looks good. Better than many other materials we could use.
Now you could argue that we only think it looks good because it’s valuable, and maybe that is how it came about, but I think it’s been embedded into the culture deeply enough that gold as a material looks great to us on it’s own merit at this point.
Aesthetic value is real value, as we can tell due to peoples willingness to pay for artistic objects even if made from cheap materials.