Florida is very hot and humid throughout the year. Do liquids containing electrolytes benefit a person when trying to walk outdoors?

Generally, yes. Sweat contains variable amounts of salt and one can lose considerable amounts when exercising in a hot climate. Salt replacement is highly recommended. Unfortunately, commercial "sport drinks" contain lots of sugar (or high fructose corn syrup) and inadequate amounts of electrolytes. Much better to add extra salt to food, or load up with salty pretzels or nuts before exercising.