- they’re lighter
- the aesthetics: I like a good steel/titanium bike, but the flowing lines and zero-joins of a carbon frame are awesome
- manufacturers can control and alter the layup to control the degree and direction of flex in different regions of the frame. Plus dampening properties are helpful.
Weight savings alone are a “Good Reason”.
Edit: Wow this article is insufferable. “You’re not good enough to have a carbon bike” and “you’re too peasant to work on it properly”. If the author wants to have an inferiority complex over what I’m guessing is a failed racing career and an inability to learn basic mechanics skills, then that’s on them. I’ve owned carbon mountain and road bikes, put thousands of K’s on them, maintained and upgraded them with zero issues.