Mine is off.
Firstly, there is no point as I can't hear it at all.
Secondly, when taking photos of someone who didn't notice you trying to take photos, no point in the beeping thing letting them know what you were doing, you may as well scream: "Hey you!! Look at me, I'm taking a photo of you!"
And thirdly, although I would image it is hardly a worrying matter, it's not like it's as power hungry as the screen so it's not something worth worrying about, but I would image if you were busy taking photos after photos after photos, add up every beep after beep after beep, it use a tiny bit of battery power, it may be a tiny bit but this tiny bit could be worth one more shutter click. Well, just my imagation.