I spent a season in LDA & know people who did a good few more. There are a fair number of deaths in the mountains over a season, if not hushed up then actively kept quiet. There was a “super black there” actually it was fine, but was steep enough to slide all the way down if you fell at the top & was south facing so had a tendancy to be very icy at times. I know for a fact the year I was there there were 4 deaths on that run alone. If a helmet reduces the risk why not, and as stated above I imagine they do keep your head warm.
Do I wear a helmet? No, I have been skiing since the age of 6 (in the Lebanon) & am now 43 so have a fair amount of experience & am a damn sight slower now than I was 10-15 years ago, however I do ensure that my kids wear them all the time, they are just learning.
I am very seriously thinking of getting a helmet for me next time I go … the problem of course is one of ego … I dont think I do anything scary, fast of radical these days ….. saying that one of the worst incidents I was at was at 0 mph when a mate was stopped at the side of the slope & another mate slipped into him at about 2 mph, at the time the medics all thought it was a broken neck (luckily it wasnt), so as with a bike it can happen through no fault of your own at a time you do not think you are at risk.
If you have no ego hangups then wear one, it will not do any harm & may do lots of good.
PS plyons are hard & I do know of people who have somehow managed to get their heads through a gap in the padding, they died there & then.