That place is just a made in Chinese Generic brand clearing house and personally I wouldn't buy anything made of carbon by a generic Chinese factory if my life depending on it staying in one piece like a set of wheels, handlebar, or a fork. If all you want is a water bottle cage, fine, if it breaks it won't kill you.
I have never heard of carbon bike. They do not even sound very solid. I believe that they are not very strong. Do you think it is cheaper to buy them. I think it is great in that way but I am not sure of how good the quality is.