The usb 2.0 standard only support 96 khz 24 bit is my understanding and the Hagel Roost manual states that the usb maxes at 96 khz and you need to go coaxial or optical on the digital side from higher res sounds. I suppose I could buy another dac and use my analogue inputs as well.
As for the hi-res argument, I need to qualify that I am unable to do much testing yet with the 192 khz files so I assume your question pertains to the difference between 96 khz and 44.1 and also 320 khz mp3 files.
I have had digital music ever since Napster was on the scene and I started with 120 khz mp3 initially, liked vbr mp3's for awhile and then 320 when they became available. I had a friend who liked digital music but was really an analogue guy (turn table) but used digital for his music player when walking etc.
He would ask if I could rip some of his cd's for him from time to time as he had a cd player as well and i used to do so in 320, stating that it was overkill at that. Then I started to get some flac and wav files in my collection and liked them better than the mp3's when it came to higher frequency reproduction. wav or high res flac are the same in my opinion in this regard. My friend asked about them one time when he noticed I had some. He is a digital skeptic and so I thought he would say they were a waste of space but he didn't, he asked if I could rip his cds in flac and I said that I could. THere is a difference if you have a system capable of reproducing hifi sound and you have flac files that come from a "good" source. Remember garbage in...garbage out applies here as well.
The flac will sound brighter (better high frequency replication). The higher bitrate flac (96 khz) if taken from a good source i.e. (high analogue master or high res digital master) is slightly better again but the law diminishing returns applies to this as well as all other things audiophile. It is logical that the more you sample a source the greater the resolution, the better the high frequency reproduction. Can you hear it, the experts apparently say no, I bought my gear and my files and I say yes.
My testing is simple, I have copies of some good quality mp3, 44.1 cd rips and 96 khz (purchased online) files of the same song. I play each file to a chosen point and then switch to the next one. I can usually hear the difference in well recorded music that is worthy of hires recording. Kiss an angel good morning by Charlie Pride for example sounds great as an mp3, Pink Floyd maybe you might hear the difference on some of their music. Of course higher res does not mean you will enjoy the song more as I have found out. So in closing I have somne music I like to listen to on an analyitical level asit was written that way and other stuff is fine in 320 mp3 (Garth Brooks, Willie Nelson, Merle Haggard all come to mind. Female vocals do improve with higher res though (Emmy lou Harris, Eva Cassidy etc.)
There you have it.....fire away if you will.
Stay safe ......