Both smart-watches and smart-phones use applications, or "apps," which are software that consumers can download and use to play games, check stock market prices, and read news stories, among many other activities. Particularly useful apps are called "killer apps." One industry analyst remarked, "There is no one killer app for smart-watches." If the analyst's observation is correct, does it make smart-watches closer or less close substitutes for smart-phones? Briefly explain.