From Wiki
USB3.0 : "There have been many reports of USB 3.0 equipment only transferring data at USB 2.0 speed, usually with a message "
This USB Mass Storage Device can transfer information faster if you connect it to a Super-Speed USB 3.0 port". This has been due to several causes, including drivers, certain cables specified as USB 3.0 (problems disappeared when a different cable was used), order of starting equipment, equipment needing to be disconnected and reconnected, and overclocked computers."
Other than speed, the dual-directional data transfer allows use of an asynchronous USB D to A. This solves the problem of dueling DAC clocks which has plagued earlier USB DACs for high quality audio applications.
Ian