As far as reducing the wear on the rigging when anchoring you need to keep the mast connected to the boat as rigidly as possible. This will prevent the dynamic loading (banging) which causes the damage.

Gel coat does not adsorb water, it allows water to seep through. It is porous. The fiberglass is what adsorbs the water like a sponge. It then goes into the foam which really wicks it up.

Gel coat is used to give the fiberglass a finished look when the parts are made in a mold. It protects the epoxy resin from UV and helps fill out any surface imperfections in the fiber glass. You can also texture the gel coat for different surface finishes.

I'm not sure why gel coat is still the material of choice. I do know that when I go to paint my boat (hopefully this winter) I will be using a 2 part epoxy paint that is much easier to apply than glecoat. I could also incorporate a barrier coat if I choose as the epoxy is not waterproof either.

I am by no means an expert on fiberglass and gelo coat, I just happen to have absorbed lots of bits of information on the subject.