For the removal crowd...
The buzzer is a nag so you don't drive down the road for miles with the blinker on like an idiot, further confusing drivers that are already over taxed with driving responsibilities/decisions. Do you really want to add to their barely achievable work load with added decisions about WTF you might do?
But, if you prefer to do that than have the nag then....
It also alerts pedestrians that you are turning and just *may" keep them from stepping in front of you.
But, these things are far less important than your riding reverie and self image (some say).