....I might use BC's for audio route prompts though.
Here's an example from JL
https://www.johnlewis.com/shokz-openmove-bluetooth-wireless-open-ear-headphones-grey/p110575797
Yes, I thought routing instructions might be one use for cyclists.
I don't know anything about the John Lewis item you refer to, but I wouldn't have thought it would be particularly suitable for a cyclist. Mine have a half-loop over the ear to position them positively (photo in my original post) while the one from JL you illustrate looks like backwards cafe-racer sunglasses that will slide off your ears -- also backwards -- at the first sleeping policeman you ride over. More fashion than kinesthetics...
When I was doing cycle couriering/delivery (For 5 years) I used an earlier version of those Shokz, for google routing, job notifications and occasionally phone calls with the client, I'd also listen to audio books or podcasts between jobs. My experience is they work fine, are comfortable and don't move about (There's a photo in the link of someone wearing them) sound quality is OK for basic stuff but quite poor for music, for my use they'd last days and charge quickly. For google routing, they're best used in conjunction with the map on a handlebar mounted phone, following the spoken instructions and using the map as confirmation, in heavy rain, I'd put the phone in a pocket and rely on the headphones, doable but not as good. The only issue wearing them is possible conflict with glasses, caps, helmet straps... particularly if you forget you're wearing them when removing something else. The price doesn't seem to have gone up, I paid about £70 in 2019, hundreds of hours use and they're still fine.
The should you argument is more complex, they are a distraction, although you can physically hear traffic over the headphones, you hear it less, you are filtering it out. I've used them a couple of times on long Audax rides, but generally choose not to.