Expensive helmets... What's the deal?

[Turkle]

Howdy, everyone. When I was a teenager in the '90s, shopping for my first "real" bike, the guy at the store told me to just get the cheapest helmet that fit. His logic was basically that all helmets protect your head exactly the same - it would be super awful if people without a lot of money would be denied adequate protection! So, with that in mind, I've always worn pretty cheap helmets. I'm pretty sure I've never paid more than $70 for one.

After a few of years of faithful service, it's definitely time to replace my current helmet, and I have no idea where to start. I'm looking around, and there are apparently helmets selling for over $300??? What?

So my question is, what on earth is the benefit of these ultra-expensive helmets? Is it just weight, or is there some other benefit I'm missing? For those of us that aren't competition racers, can I safely ignore these boutique items, or are there real benefits I should be taking advantage of? Your experiences and feedback welcomed.