Very interesting..
WHAT ARE USB DACS AND WHY WOULD YOU WANT ONE?
https://www.slashgear.com/1835333/what-are-usb-dac-explained /
"...Since a dedicated digital to analog converter (or DAC) is likely to do a better job than the onboard sound built into most computers (and whichever phones and tablets still have headphone jacks), there's a market for USB DACs to get more out of your digital music on your computer or mobile device...
...You aren't happy with the quality of the audio output of your phone or computer and want something better that brings a higher level of fidelity, possible with support for high-resolution audio formats like Direct Stream Digital (DSD for short) or 24-bit, high sample rate PCM.
That last use case has become a lot more relevant to the average consumer than it used to be... ..., you may want to harness the music's full fidelity."