Comment Re:They're worthless. (Score 1) 213
Yes the LEDs are under the computer's control. But that still doesn't make those LEDs "output devices" in the general sense of the word.
A modern keyboard is both an input and output device. At a high level its primary function is to input things into the computer; however, the USB HID communications are bi-directional communications, there is both Input and Output. The computer can set the state of LEDs and some other features of the keyboard.
In some cases, the computer can upgrade the firmware on the Keyboard which definitely requires sending output.