Carbon is a high tech material and it is perfect for the use it was made for, but very sensitive for all other conditions.
The carbon is perfect to take the load of the kite lines but not for being crashed to the ground. If you watch the kiters around, how the treat their material it is sometimes a wonder that not more bars brake.
To avoid scratches for example you can cover it with soft rubber and it is safe. And if you handle your bar with care you will have a good product for years. I have just developed a new bar. The tube is made of carbon and there are not only holes but even slots in it. I tested it with a few times of my own weight and it did not break.
But there are different kinds of carbon on the market. For kitebars it would be perfect to take an unidirectional carbon. If you take bad or cheap material you will get problems.
My first prototypes were made of Alu and the actual carbon-bar is much stiffer than the alu-tube. I first thought as you : The weight is no problem because the kite has to carry it.
But the carbon tube is just half the weight of the alu tube and it is always warm after a few seconds touch. My complete bar is not even 500 gramms and it has an integrated safety system with a lot of mechanic all inside the tube. You notice the weight of the bar if you use it in dynamic conditions and I dont want to miss my ultra light carbon-bar any more. I will never use another material again.
Greeting and good winds