I'm a semi believer.
I am a firm believer in quality cables and indeed all of my digital cables are silver plated copper. I think digital benefits especially from silver. Plated is adequate because of the very small size of the signal. Larger wires are required more for durability than ampacity.
I've reread your post twice, there is at least one typo in it, but it sounds like you asked about the cable downstram of the DAC, which is obviously analog. I don't think silver has as big a role to play in analog (my experience). I have a set of silver interconnects. They are great. I'm currently using Mundorf wires that are a copper, silver, gold blend that they claim they develioped by experimentation to see which alloys sounded best. They are very good. I do like silver connectors. KLEI are very good. I stay away from rhodium, a poor conductor.
I say semi believer because all of this can be done at a reasonable (3 digit) price and most cable manufacturers are taking advantage of audiophile high tolerance for 4 and 5 digit prices.
Jerry