"My personal view is people buy these pre-built audio server computers because they look cool."
That may be for some but I suspect it has as much to do with people being concerned with upgrading every possible component in their system to the highest possible level so as not to miss out on the n’th degree of sound quality.
My server sits in a back room with my network equipment so from my perspective it could look like a cardboard box, as long as it works well.
To the point by @fastfreight about skepticism related to digital front end equipment, I think that is related to our preconditioning that 1’s and 0’s are relatively immune to outside effects so as long as the 1’s and 0’s arrive at the "receiver" intact, the resulting isolation, error-correction, and processing will handle it from that point. In contrast, most seem to believe that the downstream analog processing (i.e., D/A conversion, amplification, and loudspeaker conversion of an electrical signal to a sound wave) is not immune to outside effects, and therefore believe the music we hear is largely dependent on the quality of the DAC, amplification, cables, and speakers.