thanks for the feedback, we will consider the possiblity of providing a better explanation of this game curve feature in our documents or videos.
but, generally speaking, please use straight line if cursor speed on screen is acceptable, it can provide 1:1 mouse movement and cursor movement on screen while using a mouse for aiming. if you change it you will have no 1:1 control.
the effect of changing a curve will depend on many conditions, and it's also a matter of personal preference.