I'm not offended just trying to educate those that are interested. So on the topic of digital transmission some of the same issues exist as in the analog domain. Attenuation of signal and interference. Now when talking about optical digital transmission the interference isn't as much of an issue but attenuation can be. Digital signals are expressed in square waves. What happens in that case is the square gets rounded off. This can lead to a "1" not reading as a "1" at the receiving end. Noise or corrupted signal can also cause a "0" to read as a "1". So while all the digital signals are simply made up of 1's and 0's, the receiving end ideally should receive the "1's" as "1's" and the "0's" as "0's". This is where cabling can come into play. I'm not saying there isn't a lot of snake oil out there, and yes I mean Monster Cable, but there are cable companies that make cable that works better even in the digital domain.
I won't get too far into it but there is also an issue of speed in digital cable that can make an audio difference as well.
Anywho, thanks for indulging me...