My approach is to try to provide the cleanest signal possible from streamer to DAC within reason, if for nothing other than peace of mind. This does not include cables made from unobtainium however.No need for unobtainium or exotic metals as long as you adhere to USB 2.0 regs, which require:
copper wire of the appropriate gauges,
a real aluminum sheath and not some aluminum vapor deposited onto some cheap, thin mylar sheet covering 100% of the cable,
a copper sheath covering 65% of the cable,
and able to meet transmission rates.
Think of all the meat you buy and realize that not one major meat packing company meets USDA requirements, yet the meat has the USDA stamp of approval on it.
Same goes for USB 2.0 compliant cables. Do your due diligence and you'll find companies that'll gladly appraise you of what's inside their cables, meeting or exceeding standards, that won't break the bank.
All the best,
Nonoise