Structurally, the benefit of CF over glass is strength to weight ratio. A properly designed CF skin will be thinner and lighter than the same spec'd all glass layup schedule. Although, in the small amount of CF used on a trad bow, I doubt the weight savings will be noticeable.
My race boats now, one is carbon over foam (divinycell) and the other two are glass over balsa, the CF boat, two people can carry the bare hull with one hand each pretty easily, and the glass ones need both hands and a little more oomph. Also, CF is not as impact resistant as E-glass or S-glass, so there is often times a skin of those over a carbon boat, but not mine. Ask me how I found out...
Cheers!