When I first took up skiing no one wore a helmet. If you had a helmet on people would likely laugh at you.
Fast Forward to today and I would say at least half the people on the hill (probably more) wear a helmet. It's not cool nor nerdy to wear a helmet. It's like gloves vs mitts. No one cares if you wear mitts vs gloves. No one cares if you wear a helmet vs not wearing a helmet.
If you have concerns about your safety and choose to wear a helmet, then go for it.
If you don't feel like wearing one for some other reason other than not being cool, then don't wear one.
I wear one because I have hit my head on the slopes before and I had a brief blackout and a huge headache for the rest of the day. Likely got a concussion. Would a helmet have helped me? I don't know ..... I will let you know next time I smack my head hard and if my helmet helps