I'll play...
I listened to audiobooks on my last tour. It was a great way to pass the time. I have also listened to music as I commuted, but rarely. I never play music loudly though, I never have. For commuting I used a pair of bluetooth speakers in a handlebar bag. I wasn't commuting in a city environment, so there was no one to annoy. I wouldn't do it in that type of situation. For what is coming up behind me, I use a mirror, much more reliable than sound, though with music or audiobooks at a reasonable level, I can still hear cars. The tour was done on trails, not roads. In town, on a commute, I really have no need to listen to music, or anything else.
If you want headphones that allow you to hear traffic as well, try these.
https://aftershokz.com