I know. I do exactly work in chemical processing in the fab. Gold is quite magic. Other metals too, but for many there are alternatives, which is hard to find for gold. The way it reacts (or rather do not react) makes it quite special, in interposed and generally wherever copper can't be used due to highly contaminating nature of copper. But you are very right about the other mentioned ones. Hydrogen peroxide can be done in a few ways and actually some of its is contracted and some made on site. Same with ammonia solutions etc.