UltraFan Pure carbon fibre is a good conductor indeed, but as
GordonR_Cape points out, this only works if the CF is bonded at a molecular level. CF in that state is also extremely brittle, which is why it usually has to be embedded in a polymer matrix. But then there's no guarantee the fibres are in sufficient electrical contact to conduct well. The other factor that's terrible for lightning strikes into a CF panel is its thermal dissipation properties are woeful. The impact site of a lightning strike gets very hot very quickly. If that site can't conduct heat away from the impact site, the spot damage is far worse than on a thermally permissive material such as aluminium. I suspect this latter aspect isn't helped greatly by a copper mesh in the skin, but the conductive aspects most certainly are.