Hello @RyanLee ,
1) You certainly wouldn't be using it to listen to your favourite music 🙂 Quality isn't the best (especially lower frequencies) and it's not that loud - as you would expect from tiny speakers. See demo here.
2) It's actually UAC (USB audio class). So after you enable it, you can select it as a speaker on your computer, just like an external speaker system via AUX (but this one works via USB). Same goes for the microphone.
3) Demo linked above.