They are worth it, if you are willing to pay it. (Kinda the definition of "worth", isn't it?)
They aren't necessarily safer (in a US DOT crash test, the highest score for safety went to a modestly-priced lid) but they offer more features such as anti-fog pin-lock, blue-tooth-ready, quietness, easy-off-easy-on, comfort, etc.
The price/value equation for one person will be different from another person.
For me the list looks like this:
MUST-HAVES
* ratchet-type strap release,
* modular design,
* high-vis color as the primary color
* fit must be "acceptable"
DISCRIMINATORS
* integrated tinted secondary visor,
* noticeably quieter than the helmet I have now
* Lightweight
* better fit = higher preference
DON'T-REALLY-CARES
* Bluetooth-ready
* Pin-lock anti-fog
So that defines what's "worth it" to me, and automatically narrows the field considerably because not many helmets that I've looked at have the ratchet-style closure. I will not shell out $600 for a helmet that is not modular, or that does not have a ratchet strap. Done. End of story.
On the other hand, if I found one that had those features as well as most or all of the discriminators, it might win out over a lower-priced model that didn't have them, or didn't have them in a way I liked.
Your criteria and must-have list will be different, so will steer you in different directions.