By canon it's for nothing more than show, assuring the deceased that the reaper has come to take the soul. She does use it in fights, but she never kills.
I just want to see what's going on here. As to the job of getting you away...that's not my field.BUT...What do you want from me? Don't tell me you're here to TAKE ME AWAY?Nah, I'm not sleeping, I'm just in the middle of meditation.What do you mean? Ah, it's you, Shinigami.No no no, I am nothing but a mere ferryman.
