In theory that's great, but the truth of the matter is the bluetooth earpieces are huge and look rather nerdy! (ya I know, this is /. where 99% of the readership probably fits that description!) You would also be amazed at the difference it takes to process an audio signal with devices specifically geared to hearing. I know that if I only wear one device, I can tell that there is a slight difference between the normal hearing ear and the one containing the hearing aid. Can you imagine the delay going from a bluetooth headset, being processed by an iPod, then sent back the headset? All of you would look like that guy off of the old Police Academy movies that had the ability to make his mouth move like he was recorded in an Asian movie, with the audio replaced by English.
finally most people don't notice the fact I am wearing hearing aids, and I don't need to carry around a comparatively bulky MP3 player.