Yes, carbon masts are better than aluminium in terms of performance. Less weight (overall and at the extremities of the boat), greater stiffness, more control of the stiffness properties during build, all of these can improve performance.

But it depends on the application. An absurd example, but still relevant to the discussion, is that putting a carbon mast on a laser will be faster, but pretty useless considering you can't race with it against other lasers...so carbon isn't a better material for laser masts.

A less absurd example is plane wings, all performance gliders have carbon wings, but I can't think of one commercial plane that has carbon wings. Despite all the known benefits, someone has decided that aluminium is going to be "better".

Horses for courses...

Speaking of timber masts, has anyone tried to buy one recently? I've looked into them for other boats and they are more expensive than equivalent carbon masts! I've even read a story of, I think, a classic J boat which bought a carbon mast and painted it with a timber grain because it was cheaper than making a timber mast!