My point. Most people are not mountain biking or racing.
Ride a bike on the road with traffic and you’re taking your life in your hands. Hit the wrong road hazard with a street tire, and you’re going down. Zig when a car’s driver thinks you’re going to zag, and you could be dead. I’ll grant you I never wore a helmet in those days, but I’ll wear one when I get the mountain bike together. And clay is a lot softer than concrete or steel.