Useless Devices that Make Us Feel Good
Bicycle helmets are kind of like those airplane seat cushion “flotation devices.” They are endlessly hyped yet rarely needed and of dubious usefulness when deployed. Whether crashing at sea or getting hit by a speeding car, neither the seat cushion nor the bike helmet will save your life. Its funny, we heavily regulate airplane design and manage air traffic very carefully to avoid collisions and crashes yet we mostly just let car drivers speed through our cities, while pedestrians and cyclists have to make do.
Good overview here in Grist. Main point being that helmets add very little to safety, but attract all the wagging fingers if not worn. The real danger is the car and roads designed for speed rather than mobility, of everyone, which means slowing car traffic, not forcing cyclists to wear dubious devices.