There are mainly the following reasons:
1, weaving conductor inductance.
2, pore cause braid the direct coupling between inside and outside.
3, usually woven layer is the lowest resistance path along the wire, it has to do with the distance between the inner conductor is near and far to change alternately, this situation made the current tends to inner conductor skin effect is weakened.
4, woven wire spiral path, make the coupling effect between the two opposite braided wire.