Helmet or not

Guys, whats your take on use of kite helmets? contrary to the evidence on use of bicycle helmets or seat belts in cars, there seems to be limited (scientific) data on the impact kite helmets might have, i.e. preventing injury etc. I have used a helmet ever since I started kiting in 2001, also as I have been into snowkiting a lot. To fall on icy snow is like to fall on concrete. Having moved to OZ a year ago, I realized that sun specs are a must to wear. A helmet keeps the sunnies in place, which is quite practical. Apart from that, it blocks some of the sun in the face, and keeps you warm in the chilly season.
But how about the safety aspect? How many of you guys own or actually use a helmet, or have experienced situations when it was a good thing to wear? Also those of you using a board leash, whats your opinion?

Thanks! I did not see that link...