Since the invention of the typewriter, the QWERTY keyboard layout has dominated the most important interface device for typewriters, electric typewriters, and right through to computers. Not much has changes over the past 130 years or so as far as the keyboard goes. Today, so many people use computers for so many hours at a time that keyboard manufacturers now add warnings attached to the device to warn against prolonged use.
Ergonomics is the science of design as applied to the fit between a device and its user. By designing a device with ergonomics in mind, the result can be greater productivity, fewer injuries, and generally higher satisfaction with the device and its outcomes. When it comes to keyboards, anything that helps people more comfortably spend hours in front of a computer is a welcomed addition.