I’m not knocking your idea, I still think it’s cool and want to see it. I appreciate that I am far from the smartest person on this forum so I was asking in earnest. Points 2, 3, and 6 are definitely legit, the rest… I don’t see a benefit over wireless bluetooth buds like these ones for example; you’ll still need to carry them, charge them, you can lose them, they can be stolen, etc… I’d argue that one of those earbuds would be far more discrete than having that thing on the side of your head.
Answer: So I don’t have to carry the card, I can’t lose it, it can’t be stolen. You still need to carry/remember/charge/etc the external portion of the sound processor.