Because when run thru a synchronous digital output it eliminates reclocking at the DAC level. This is thought to produce less jitter and thus a quieter, more detailed presentation vs running thru noisier USB.
Of course there are many variables but it provides another option to see what produces the best sound. Results are going to be very system dependant.
Of course there are many variables but it provides another option to see what produces the best sound. Results are going to be very system dependant.