Starcraft is not a good example, because to play at any level above average, you need both keyboard and mouse.

Neither one is optional. Also the actions undertaken by keyboard/mouse in Starcraft are generally not equivalent, e.g. you cannot select a hotkey group of units with a mouse, unless you select the same units visually where they are, which will always be slower. Same way you won't be making a selection box with a keyboard. Although possible, it is far less precise than a mouse.

In other words, there are certain subsets of actions for which the keyboard OR mouse will always be faster.

This is contrary to operating in a text editor or doing configuration in shell vs gui, where some people have a legitimate preference for doing it with a mouse vs text.