If ruling out risks by a priori is a solution, why wear a helmet at all? Maybe you won't hit your head when you fall. Maybe you'll land in water or on a satin pillow (low friction).
Sure, buy all the safety equipment you can afford that has any possible benefit.
What’s better: a $15 more expensive bike light or a $15 more expensive helmet with MIPS?
How are they testing it in the lab? How do concussions work in realistic situations (is there one way?)? What is the distribution of realistic situations?
Maybe the benefits are better in realistic situations; maybe the lab tests are more aggressive than reality or the results are interpreted conservatively (because scientists spending years on something might have thought of a 30-second hot take), ...