I’ve noticed a difference in vibration damping on flat bars going to CF. Not massive but it is there. Likely makes no practical difference on a town bike, but on a MTB ridden in rough terrain it does.

The.differwnce is more noticeable with drop bars.

Whether it is “worth” the extra cost for that and the weight savings is entirely subjective

I don't screw around with cheap CF bars. I stuck with reputable brands,