CF tends to fail catastrophically whereas metal does not
**slow clap**
Both can fail in either manner. If you assume that metal parts will always bend before failing you could get a very nasty surprise indeed!
To the OP if you won’t enjoy riding it because you’ll be worried don’t buy it! I sold some carbon road wheels because I couldn’t really bear the thought of crashing them in a race.
I do/have used carbon frames, forks, bars, stems (although pointless), seatposts, saddles, bar ends, brake levers, rims, hubs, mechs, shifters, cranks and bottle cages and not had anything fail catastrophically (except for the forks that snapped (with the aluminium bars and STI) when I rode them into a car at >30mph. The extremely light carbon frame was fine. I also had a 1994 Trek road bike which is still going now.
Personally I have absolutely no qualms about using carbon!