The USB 2.0 ports might be used for a USB keyboard and USB mouse, but the user may have far more than two additional USB devices to connect to the PC at the same time, and many of those might be capable of USB 3.0 operation.
The USB 3.0 SuperSpeed path operates at a raw bit rate of 5.0 Gbits/s, while the USB 2.0 path operates at 480 Mbits/s (High Speed), 12 Mbits/s (Full Speed), or 1.5 Mbits/s (Low Speed). Within the hub, only the port power control logic is shared between the USB 3.0 path and the USB 2.0 path, since there is only one 5-V power path in either USB 2.0 or USB 3.0.
