USB is a direct high speed digital connection to a PC that allows you to bypass the need for a soundcard entirely, resulting in cleaner, consistent sound. Combined with noise cancelling technology the USB headset significantly improves accuracy in speech recognition quality, particularly in environments with a lot of ambient noise, making them a perfect solution for the busy workplace. 

Also, with the growth in home working the USB also offers a simple, reliable solution that allows the user to connect easily to any PC.