I have always had customers who ask about “those hearing aids that go on your glasses”, but now the new thing is bone conducting headphones.
Hearing aids first, get them out of the way 🙂. The type of company who put these adverts out are not the type of company you want in your home. The advert is misleading, and I pretty much guarantee you will be told you‘re not suitable for them. Because spectacle-attached hearing aids would be rubbish, even if you were in the very small percentage of people with a conductive loss (middle ear/outer ear problem, perfectly working inner ear).
Headphones then, wouldn’t it be amazing to listen to music through bone conduction while keeping your “ears open”? Unfortunately, all detected sound goes through the cochlea to the brain. You can hear multiple sound sources at once (it’s a fantastic thing, it really is fascinating stuff), but just like with any headphones, if you are listening to 70 decibel (dB) music, you won’t hear the 40dB footsteps of your robber, because your cochlea is already occupied with that sound.
Personally, if I had two working ears (I don’t), I would wear an AirPod in one ear and leave the other one listening for traffic noise/robbers. Best way to make use of how your hearing works, but would probably still take away your attention from surroundings.
Sound quality wise, bone conduction through skin is not going to knock your socks off (that’s why they implant bone anchored hearing aids into the skull. They don’t do it even though a headband works just as well). It works best over a limited frequency range, and even then only up to certain volumes. So not much bass range, and I would suspect no treble. We only test 500Hz to 4kHz (the middle chunk of the hearing range) with bone conduction, for good reason. So it will sound like a poor reproduction, as you’re only getting some of the music track/speech sounds.
At most normal listening volume levels, the vibration of the unit will also vibrate the air itself - like the inside of a speaker does. So everyone else will hear your headphones too!
And finally, bone conduction only works if it is gripping your head 3/4 of the way round, so if it doesn’t pinch a little, it can’t transmit.
Sorry to be a downer! I am sure some people are getting on fine with these if their expectations are low, but I wouldn’t recommend unless you really can’t use existing tech. And make sure of that money back guarantee!