• they are cable-less, thus need to be charged separately

I'll give you that, but my bone conduction headset lasts a few days with the amount I use

• they are cable-less, thus it is easier to lose them

Meh. I've put corded earbuds in my pocket and probably worn them out faster that way. Bluetooth headsets I tend to leave on (much to my wife's annoyance) and that makes them last longer in my experience.

• bluetooth implementation is a potential security vulnerability

Aha, that van outside must be tapping into me listening to The Dandy Warhols! I knew it! (In all seriousness, if security is that critical you probably shouldn't be doing whatever it is over WiFi, which is pretty much unavoidable with a phone)

• transmission by radio will always be less energy efficient than transmission by wire

Are we really talking about saving energy here? That's like... Moisture in the bucket levels. Not even a drop in the bucket