Bench testing helmets is quite different than practical use. The data is still being collected about the changes in concussions and sub-concussive impacts.

The bigger indicator of prolonged recovery from a concussion is not additional bumps. It is a pre-existing condition of anxiety or depression. A pre-existing anxiety and depression condition exists in something like 80% of prolonged PCS. They can use pre-existing anxiety to predict a prolonged recovery.

Wearing a helmet can enable the OCD/anxiety behaviors of such a person.

Encouraging others to become just as anxious and obsessive by using a helmet can be counter productive.