twoleftears,
I agree with you. There are advantages, at least theoretically, for coupling the two together. I have a Naim 555 server/DAC combination. Different sections of the combined unit are served with their own power feed from the separate dedicated power supply (separate box). The most noise sensitive section is enclosed in a faraday cage. In order for the digital signal to enter the faraday cage, it is first converted into an optical signal so that the signal passes optically into the faraday cage (noise/rfi cannot come in riding on an electrical feed). This sort of complete engineering makes sense.