I think the best way to imagine it is to imagine your total effectiveness as combination of the two attributes - you call them Speed and Brain. I think your total effectiveness is best modeled as Speed times Brain. Increasing either one is useful, but increasing only one is not as helpful as increasing both. If
If you have a 10 for Brain but a 1 for Speed (IE you know exactly what your opponent is thinking, but you can barely use a mouse), your total score is 10. If you are as dumb as a pile of bricks (Brain 1) but have great mouse skills (Speed 10), you might also have a score of 10. but a guy with moderate brains and fingers might have a score of 5 times 5 or 25, which would beat both of the extremely lopsided guys. And
Finally, note that if you watch a lot of vids and up your Brain score by 4 points to 9, you're a 9 times 5 or 45. If you instead watched some vids and practice some "Speed", you're now 7 times 7, or 49. In other words, try to balance out both strategy and execution.