Thanks for your post (never thought of such things until your referencing)
Ok so that's a separate DAC and how to utilize the USB (digital out) rather than the headphone out (analogue out) which I get it......Well kind of, actually, sorry to be single minded and all that... But why the hell would I want to do that, hmmmm ok dont answer that!
Moving on then (actually one last thing)..
When you say more control over the volume, not sure if you are talking about the number of steps for vol + / - typically 7 - 15 on the device itself, but if you are - the way I deal with that is I use xposed installer and the module called xvolume30. This allows me to (you guessed it) set the phone to have up to 30 steps if I want it (it works too).
Ok so I lied (one last thing)..My In Ears (I paid full retail) were £ 90.00, what are you using and how much, presumably the spend was to get the best out of the DAC?