I find it incredible that we still are "debating" whether to use safety gear or not.
The answer is yes, we should all be using it, no matter what.
1) The only possible reason for not using an helmet is because it does not look good, which means that you are a man or a woman with not enough self confidence. I enjoy a lot debating on the beach when i find people asking me "why do you use the helmet?". It's such a stupid question that i always have a good 30mins in stucking in the guy's head that the fact that he does not wear a helmet does not mean he's cool and i'm not, it means that my balls are bigger than his as i have enough self confidence to know how cool i am, while he doesn't.
2) An helmet does not reduce in anyway the fun. It's different, say, than not using an helmet on a motorbike. When using a motorbike, objectively for most of the people is much more fun to ride "free", as the feeling is different. It's still stupid, but at least there is some logic behind it, debatable, but still logical.
3) There is no thing such a "risk free" condition when kiting. There are more or less dangerous conditions, but it's always a risky sport. There are a gazillion situations, in any condition, for why your board can ultimately end up hitting your head, even in perfect consistent 20 knots glassy water.
4) You won't need an helmet, or safety gear, probably in 99% of your session. You wear safety for that 1%. Now, that 1% of mess, which WILL happen, can end up from something like having a big knock on your head down to you dying. Is it worth it? Go to a shrink if you feel you need to ride helmet-less because the others do so. Even better, push it hard so that while they ride and look cool, you outride them performing stuff that they can't even dream of. That is cool.
5) Real life experiences:
I had a fantastic chat once with a guy in Brazil. I was explaining why i prefer riding with an helmet, he was explaining why it's not cool. While talking, he keeps on asking me "can you talk a bit louder". In the end, i found out he couldn't hear me because he broke his eardrum on a kiteloop landing. When i found out, hell yes, he really felt like an idiot.
Once I had a tremendous loop (didnt want to, my mistake) gone wrong, 40knots gusty, crashed uber powered, helmet knocked off my head, 10 seconds without breathing for the punch with an impact, a good 50cm of my body which were blue for the next 15 days, but i was still riding 10 mins later when i recovered.
On a beach in Venezuela, i chat with an Alpha-male like who was bragging about how good he was, can do this and that, F16 one handed, etc. Then i go "listen, why dont we go out together, i'd like to learn a couple of easy tricks, i can watch and try to learn from you". Answer "sorry i can't, actually i can only ride, had a bad crash and broke my rib". 10 minutes before he was trying to convince me that using an impact is useless.
Now: am i perfect? No. Do i care about looking cool? Yes, i'm human and not as self confident as Brad Pitt, if i have my girlfried taking pictures i will probably ride naked with some make up done before because i do like to have those "cool" pics to show-off, but i realize it's stupid, and i do it on 0,1% of my sessions. And it's still wrong. It's basic risk management.
Is safety gear a guarantee that you are safe? No, just like safety belts in cars aren't. It simply gives you 10x more chances to keep on kiting instead of going to an hospital.
When you see someone looping a kite on the beach and enjoying sliding for 20 meters on the sand you are not seeing someone cool, you are watching at a candidate for next year's Darwin Award.