You're assuming this is a sequential workflow, which it isn't. Animation is already done by the time you hit a target. I also am fast with the mouse, I used to play and design competitive FPSes for a living, that's precisely why without measurement and considering actual scenarios I have a really hard time believing that this specific thing actually slows anything down for real use cases and isn't just your personal preference/imagination. I disable it too but it's just my preference, as I find it distracting and breaking the focus.