There may be other advantages (galvanic isolation; equipped with a linear power supply) but for me it was simple...
the Gungnir DAC I bought did not have USB input (only BNC, RCA & Toslink for digital inputs). At first I was using a Musical Fidelity V-Link 192 to convert USB to SPDIF to enable listening to USB output from a Macbook Air (now from an Aries Mini).
USB advanced over the years. I purchased the Eitr as an upgrade to the V-Link and because it incorporated Schiit's latest (5th gen?) implementation of USB, plus I really did want another piece of Schiit in the system :-) Someone buying a DAC equipped with USB input wouldn't necessarily need the Eitr.
