Ok, I don’t understand that. What I am saying is that electronic noise is coming from many sources, including for example a Raspberry PI. The noise then traverse the DAC and affect the analog section of the DAC which in turn affects the sound after being amplified (muffles the sound, hides details and so on).
A good example is to connect a DAC directly to a regular computer. The DAC will still receive the bits, but it will also receive a lot of electronic noise from the computer, which affects the sound a great deal. By using a streamer, ethernet cables (and their opto-coupling) will remove most electronic noise. Using a pair of media converters and fiber will further remove noise (in fact, it will remove all noise up to the fiber, but the last fiber converter will produce its own noise).