Speed of K is a term I saw in a programmers forum. Standing for “speed of keyboard” it asserts that most things can be accomplished faster if you learn to do them from the keyboard instead of through the use of other input devices such as mouse, touch, and voice.
There is a long history in this debate. The mouse was chosen over light pens, for example, partially because task switching from the keyboard was expensive.
There’s perhaps another rule here as well — the Speed of T, or Text. All these years into the evolution of the web, text still remains the quickest way to transmit and receive information.