From a boat builder whose spent most of his life finishing wood around salt water. Spar varnish is pretty good but will eventually break down and need to be refinished, not that that's a big deal. It's the UV, it breaks down darn near everything eventually. Same for epoxy coating except since it has no UV inhibitors it's life can be pretty short. The wax treatment will penetrate the pores of the wood and seal them off for a while and works pretty good. It will break down eventually as well. Thompsons Water Seal will do about the same with a similar life span. Nothing wrong with bare wood. It will age some and maybe check here and there and turn gray eventually. It really won't make the wood stronger. That sure would help a wooden boat if it was true. You won't be in the water long enough to fully saturate the wood and in between hunts it will dry out. It's sort of a pick your option, they're all acceptable deal.
Traditional marine woodwork was often treated with "long oil". I've used buckets of it over the years. It's oil based spar varnish mixed with more or less equal parts pure tung oil (and not the tung oil finish that's sold in stores, that's mostly solvent) then thinned about 10% with turpentine. Put it on with a rag, wait ten minutes or so and then wipe away ALL the excess. Recoat after 24 hours. Two or three coats would probably last a year on a scoop handle used every weekend. To refinish just lightly sand a do it again. I've got traditional wood oars that are 20 years old that have never seen more then that.