Traction was made intrinsic because, after the Mobility bonus was removed, M+K users had zero reason to use it thanks to DPI settings. Controller players on the other hand could not adjust their in-game X Axis sensitivity to match the potential turning speed afforded by Traction. This disparity between M+K and Controller users came into sharper focus as the devs began preparing for the implementation of Crossplay, as even a 0 cost mod (at that point) taking up a mod slot for Controller users put them at a noticeable disadvantage compared to those using M+K. No such disparity exists in terms of Fastball. Any given grenade will have a specific throwing arc without Fastball and a different throwing arc with it equipped, regardless of input device. As such there isn’t the same impetus to make Fastball intrinsic. (΄◉◞౪◟◉｀)