Steve, I'm surprised at your question.
What I'm talking about is the fact that depending on the quality of the design digital noise can couple between different parts of the circuitry in a component, via grounds, stray capacitances, etc. Potentially/theoretically resulting in increased jitter at the point of D/A conversion, and/or effects on analog circuitry.
Where did you get your EE degree?
BSEE Columbia University
MSEE Rensselaer Polytechnic Institute
+ 33 years experience designing and managing design of analog, digital, A/D, and D/A converter circuits for defense electronics.
In any event, the bottom line on both of our posts is the same: Implementation is what matters.
Regards,
-- Al