FWIW Watco is a mix of oil and varnish. It is pretty, doesn't build a film, and will blotch with exposure to moisture. It's not the worst choice in the world, but there certainly are better. It may be just fine to refresh a factory finish if it is going over the finish, rather that on naked wood. It can't be worse than regular oil. It is an interior wood finish, and furniture that has been finished with it will get rings if you leave a wet glass on it.
If you are looking for a finish from a hardware store, maybe poly that has been rubbed out to a matte finish? Get a wiping poly or thin standard gloss poly to 50% poly 50% mineral spirits and wipe on. It can be done without looking too glossy.
