@@TheRealSimeon its so you can have your W maxed that much quicker over Q while still having the early game dmg Q offers. W is your most procced ability on AP since you want to be proccing it with your R/E and your Q so having it maxed early gives you that much more dmg. If you're playing just for the R-WQ one shots you can just fully max Q instead. But if you're playing to make use of all your abilities you do the 3 points version.