Sony's PS3 Bluetooth headset costs $50, seems pointless

I’m not sure what the idea is here. You wear this ear-thing while you’re playing the regular sound over your speakers? So do you hear the other people’s voices in the headset or in the speakers? Or both? Is this item really necessary? Someone enlighten me.

I guess you can buy one if you feel incomplete without one on your ear, like some people I know. Used to know, anyway. They’ve all been cut up and fed to the pigs gone to Chuck E Cheese!