CF rims are not inherently more fragile. They can be a lot stronger than AL at the same weight... or a little stronger at a little less weight... or just as strong for a lot less weight.
This has been pretty well settled in the MTB world.
Not sure if this has been posted:
The fact that some stupid light CF rim failed is not an indication that there is a problem with CF... it is that someone tried to take the lightness thing too far.
Now, is it “worth” it? Depends on your financial situation. The benefit of CF is going to be the same regardless, but the pain in one’s wallet or purse is going to depend on how fat said wallet or purse is.