Very informative video, I recall watching it a while ago. I have never been a believer in paying huge dollars for a helmet but don't like cheap no-name one's either. I have crashed lots in my MX days as well as a few on sport bikes and never have had any head related injuries. Most important to me is good snug properly fitting one which has a good rating beyond DOT, Snell or ECE, MotoGP require ECE rating. I usually look to the mid-range price point Scorpion or HJC which fit my head shape the best. The top price brands are of high quality when it comes to materials and overall workmanship/details and do tend to last longer IMO but I don't believe they are necessarily safer in the event of a crash.
Sunshine and my ride is all I need...
2018 Ducati Supersport S, "Solana"
2017 Ducati Supersport S, "Annabella"
2006 Honda CBR600RR, "Red-Rocket"
1990 Honda VFR400 , "Baby V"
and a dozen more previously owned bikes