If i'm in bindings and my boards hitting my head then i've got bigger issues to worry about than wether i'm wearing a helmet or not haha!
Some of the risks are death, paralysis, memory loss, permanent cognitive impairment and early dementia, plus potential minor bonuses like chronic headache and mood swings that will make it hard for others to get along with you.
Your relationships may suffer or end.
You won't be able to tolerate alcohol so well either, your partying will probably end too, if that's something you're into.
Get a little more experience and you will meet people who have been though these things.
Even if you ride a nice slow 10-15 knots loading for the next wakestyle trick, all you have to do is accidentally loop the kite, miss a pass, tangle on a bar end, impact a feature, etc, and you can be hitting the water (or something harder) near or even above windspeed. Or get a bit more air than you bargained for, over-rotate etc. Catch an edge or tip and your head can hit first.
Not a huge worry in 12 knots I guess, but 18? 20? 30? Not so good.
How will you manage to set up your trick wrong, miss the grab, and then go in head first at once?
How could you accidentally loop a slow kite set up for wakestyle?
Will a gust hit while you are hitting a feature in water just a little too shallow?
Will the tide or wind take away that extra depth of water you need to carve a transition or land a jump?
Will someone else lose their kite and have it hit yours?
Maybe, and you can't always do anything to prevent it.
Accidents are a series of small mistakes or random events that happen in sequence.
Maybe your only mistake is not trying to protect yourself, it doesn't matter, the result will be the same. Not everything is under your control.
Conventional wisdom is right about helmets.
Wear them, at least when you are throwing tricks, riding in crowds, or when the wind is strong.
The G-force comes from decelerating your head in a short distance.
The helmet adds an inch or so of distance and bit of time.
It adds some area, but not that much.
I guess an alternative would be to shrink your head to a smaller diameter.
I think the helmet is a better option.