Because when it oxidizes it will still conduct. Those of you who've owned some copper zip cord for years may know what I mean. I recently stumbled on some silver plated zip cord by a company called Knukonceptz on Ebay, but they have a website also. Polyethylene insulation too. 12ga. is 1.49ft. I think this company is mainly in the car audio business but I bought some of this and it works fine in my home system(imagine that). For people who plan on keeping the same stuff for years I think silver has it's advantages as you won't need to buy it again unless you need longer runs. Acoustic Research makes an interconnect cable with some locking rca connectors that is silver plated and double shielded. Just thought others may be interested in some cheap alternatives that will last for many years. This btw is a most refreshing site when it comes to wire.