There are so many types of headphones that don't isolate much, including the cheapest crappy on-ears from the walkman era, there's really no excuse.

And on the few occasions where I've had no other option, it made so much more sense to set my phone to low volume and bring it close to my ear instead of holding it iut and maxing the volume.

And if I need to talk as well, many people don't know this, but there's a second smaller speaker on the opposite end of the phone, approximately one mouth-ear distance away from the microphone.