That's how I felt at first, but in 10+ years playing SC I've found the opposite. High APM is important for two reasons: a) Scouting constantly, producing units,

That's how I felt at first, but in 10+ years playing SC I've found the opposite. High APM is important for two reasons: a) Scouting constantly, producing units, upgrades, building buildings, attacking, harassing, retreating, maneuvering. With multiple units/control groups. There is a ton of stuff to be done. b) Optimizing the workqueue, ie. is highly correlated to how good your multitasking is. For instance, leading two units to scout in 1 sec is not good enough if you send them to the same path because your accuracy is bad. Sending them to two different meaningful locations, with a plan for each of them, is. However, correlation does not imply causation. It should be noted that high APM does not make you good, but your APM will go up while you're getting better. Think of it as obtaining a natural aptitude with the game's mechanics. After a while, it may develop as a bit of a reflex, leading to high spamming APM, but there's no doubt that during that time, the player is 100% prepared to squeeze every single bit of (meaningful) actions into all that "spam".