Makes the screw go in a $#*! of a lot easier! Many old framing hammers had a hole in the end of the handle for bees wax. It serves the same purpose for the nail. Not a big deal when framing with douglas fir or hemlock lumber, but my father-in law's house was built during WW II out of oak. He built the house himself and, with the war on, lumber was rationed. He felled a couple of big pin oaks on the farm and had the logs milled into the framing lumber for the house. In the 1990's, after 50 years of aging, the wood was so hard I had to drill holes in the oak to drive in a nail. Then he showed me the trick with the bees wax on the nail point and they went right in without the drilling.
Actually, my own father had built an 18 foot mahogany boat when I was a boy and he put it together with about a thousand brass, straight slotted screws. He used bar soap on the threads of all the screws. It eased the torque required to drive them so that the heads didn't get buggered up.