One thing that I see Chris doing in his design: Minimizing Noise. He goes with low noise components such as power supply etc. A very wise thing to do. While this will have no effect in the digital domain, it could be injected in the analog one after conversion. The server could very well emit noise that is picked up in the amp etc. Noise has a cumulative effect with each source possibly stacking up to make a much louder one. So reducing it in the server is a good thing.
That would include using a high end USB interface. It is possible that some noise could get transferred to the DAC and end up in the analog signal at some point. A good DAC would minimize this beyond the range of human hearing. But why take the chance? If you building a no holds barred audio experience, then you should take every opportunity to eliminate noise.
And just so we are clear: All of this noise will have 0% effect on the digital signal. It will not appear in it in any way, "flip any bits" in the computer or DAC, or otherwise affect things. None. In the analog domain, it may appear as noise. And it will sound exactly like any other analog noise: AC hum, "modem" sounding computer noise, hiss, etc. There is nothing magical about it. It is just plain old noise. It doesn't make it "less resolving" or "less open" or any other non technical mumbo jumbo. If it is below the range of human hearing, it has no effect that you can hear. And if you measure or graph it, it just gets added to the signal and ends up sounding like: the exact same thing. It doesn't magically modulate the signal or somehow or take away from the audio signal in a subtle way. It just adds the wave of the noise to the signal and that sounds the same to the human ear as if the music wasn't there.
The point is that in digital audio you are only dealing with the same things that you do with analog. Nothing special. You don't have to worry about some magical effect on the digital signal, clock timing etc with the exception of the DAC. A garbage DAC may in fact have some audible problems. A cheap DAC will likely reproduce the signal without any difference from an expensive one. An expensive DAC will spare no expense in protecting the analog signal from noise etc. It will also go the extra mile as far as clock timing etc. Not audible, but why "take the chance" if you are an audiophile and appreciate the best. That is what you are paying for. Their marketing may say things that appeal to the "magical types" but why not? Marketing is mostly lies anyway. Do you believe every commercial on television? Have you ever read the fine print? Spend the money if you wish, but understand the actual benefits you receive.
What I find hard to understand is the amount of time some people spend reading pseudoscience. They spend hours and hours listening to and believing the "experts". Keep in mind that the "Weekly World News" has plenty of scientists and doctors to write about with magical claims too. Just because someone has a title, doesn't make them correct. They are in that magazine because they made the same claims to their peers and they rejected their "science" because it was flawed. If it were in any way valid it would be in a scientific journal. And to give you some idea of what kind of information can appear in legitimate journals: Things written by grade 8 students for science fairs. Things written by enthusiasts with no degrees or titles whatsoever. If it is something new, relevant and backs up claims with actual science it usually gets published. So why aren't the audiophile "experts" having their work published in one?
If you love audio so much, why are you not spending some of that time understanding the conventional science as well? That way you can make an educated decision as to whether they are full of it or not. Most likely you will also know how to spend your money wisely and create an ultimate listening experience by putting the money where it is most likely to be heard.