I always wear one, because:
* it protects my eardrums (friends had their eardrums blown out, no need to risk that)
* it's a good sunscreen
* would give me some extra protection in case of an impact whatsoever
* it does not disturb me at all (helmet: SR super scrapy)
btw: every serious freeskier wears a helmet, the same is the case in wakeboarding, mountain biking... strange that some kiters do not get it..
but i observe a clear tendency towards helmets: in vignola (sardinia) some weeks ago, EVERY kiter on the water (about 20) was wearing a helmet. All ages, levels, several nationalities present...
the same observation in beauduc: helmets get more and more widespread