The tendency is to compare digital signal transmission to a telegraph. After all, the dot-dash DC circuit of the telegraph is similar to the 0-1 of digital. And like the DC circuit of a telegraph the voltage of a digital signal is either 0 or 5 Volts. We tend to imagine an analog wave form as something like a +/- sine wave or combination of sine waves overlapping. Digital signals are waves too. They do not cross zero but they have a bias of 2.5 Volts. ie. over time the average voltage of a square wave of a digital signal will be something around 2.5 Volts. That means the digital square wave "zero crossing" is at 2.5 Volts. Given that these square waves are propagating at 5 MHz and higher, they share many properties of analog waveforms. They can experience phase shift due to capacitance or inductance and they can pick up distortion although their tolerance for distortion is much higher than analog. On the other hand, digital signals for streaming are less tolerant to phase shift or timing.
Ethernet and USB cables have an impact on the sound of streaming music that many claim is impossible. Meanwhile, audio hobbyists may not fully understand why or how but find ways to improve and move forward the state of the art.
Maybe I'm talking out of my hat here but much of what we experience with streaming hifi manifests itself more as a wave than not.
