I got into an argument with someone once about this, when they told me (paraphrasing) “it’s safe to drive listening to music through headphones, because they let outside sound in”.

Yes they indeed might, but - even ignoring delay introduced from digital electronics - you’ve now lost all sense of where that sound is coming from, because you’re listening to the sound of one microphone being played through one speaker.

The human ear really is an incredible thing.