The initial finding that helmets protect your heat have never been replicated in any good scientific study
OK, I realize this is a contentious issue and the data in favor of helmet use is mostly anecdotal since it's impossible to replicate an accident with and without a helmet and compare the outcomes. No one has done controlled, instrumented crash studies I'm aware of. That said I can add two anecdotes to the evidence as I have destroyed two helmets in bike accidents.
One was a slip on a slippery road at a walking speed. The bike simply went out from under me and I landed on my right side. I had a chipped shoulder blade and a mild concussion that wore off with no lingering effects later that night. My helmet was cracked in three places from the impact. I can only conclude the helmet prevented more serious damage.
My second accident was the result of hitting a big pothole in a poorly maintained road shoulder when a passing truck got a bit close. That one caused a Grade 3 shoulder separation and a concussion serious enough that I don't remember a thing from the accident time about 4:00 in the afternoon until I woke up in the hospital at 7:00 the next morning. Fortunately, again there have been no lasting effects. And also again, the helmet had several cracks and was a throwaway.
You will never convince me that helmets aren't beneficial. Don't conclude I'm just accident prone as those were the only incidents in 31 years and 205,000 miles of riding.