Hacker News Reader

Well, ignoring spam clicks, APM is a measure of the number of decisions that a player makes throughout the course of the game. You'd expect a player making more decisions to come out ahead in a game as fast paced and action oriented as Starcraft.

It's clearly correlation. A pro will still play at a high level with mouse only, or even keyboard only.

Example keyboard only game: https://youtu.be/cY0d2kHzrxY

it's largely overvalued, but you probably can't be a pro without at least ~150, slightly less than 3 actions per second, increasing as the game goes on.