iusb3mon.exe monitors and manages the USB 3.0 ports. Basically it's there to monitor any powered devices plugged into your usb 3.0 ports
Since it is not a driver, disabling it does not prevent the USB 3.0 ports from functioning. However, it should not be disabled as under certain conditions that may cause unexpected behaviour.
Don't end processes or disable startup items unless you know what the consequences are likely to be, or unless you know for sure it's related to malware for example.