Coaxial cable has a good shielding for it's outer and inner conductor, this setup reduces a lot of noise and can be operated @ higher frequencies than shielded and twisted pair!!!
hi
co axial cables has less attenuation than 2pair sheilded cables
and the capacitor between the core and the outer sheild is smaller than the 2pair cables that mean it may handle higher frequancy .
the cat 6 twisted pair cables are higher in performance for network applications as the twists in the pairs make each wire in the pair face the same amount of the interference and noise and then cancel each other