Cyclecraft by John Franklin points out that much dangerous driving is noisy – revving engine, harsh braking + the ubiquitous horn from an impatient driver so for basic safety reasons, no.
Personally riding on the road has enough hazards already without reducing my ability to pick up on them…
I suspect sooner or later some lawyer will use contributory negligence against a cyclist who’s been hit by an errant driver because they were wearing headphones – there’s enough nonsense from the Police about telling cyclists to wear hi-viz which isn’t even a legal requirement