I was resisting, but I too am curious as to the reasons why copper carries 1s and 0s better than glass over moderate length runs -- all things being equal.

If toslink works, it works. If coax works, it works. It is my semi-educated understanding that digital is not as sensitive to cable quality as analog. If the receiver is getting a stream of 1s and 0s, how does one cable provide a better stream of 1s and 0s better than another?

Unlike analog, digital signals have no gradients of info along a spectrum. It's on or off.