1.) Iodized salt provides the body with iodine, a necessary mineral
2.) It is totally delicious alone or as a flavor enhancer.
3.) Sprinkled on ice, it provides traction to prevent slipping. It also helps hasten melting of said ice.
4.) Although modern conveniences like refrigeration make this less common, salt is a great preservative. Colonists and pioneers were probably pretty grateful for salt.
5.) Table salt is just abrasive enough to be a fantastic cleaning aid (e.g. tea stains in mugs) while not likely to scratch what it is cleaning.