Lack of awareness? How about having a radio in the car or, worse, (hands free) calling? Or even having excited conversations with three others in the car, that surely gets your attentiveness down way more than music on a bike.
My town is very bike friendly, and my 4 mile commute to work is 90% dedicated bike roads, but I still wouldn't bike without the ability to adequately hear things around me. Every once in awhile I come upon a cyclist with headphones or ear buds, riding in the center of the lane, and when they fail to hear my call to them that I'm on their left, I pass them in the available space and they almost always end up getting spooked. Same thing with runners and headphones.
It allows you to hear things around you. It's similar to holding a speaker aside your ear (but not blocking it). You hear the music, but still hear other things too. I use it while cycling to listen to audio books. Works fantastic and I lose no situational awareness.
Get one of these instead: https://www.amazon.com/Aftershokz-Wireless-Stereo-Headphones...