It is a truism that the application of an invention that eventually becomes the most commercially successful often was not even considered originally by the inventor. Take the computer-programming language, Java. In the beginning, its inventors thought it would be used to control the environment in the home (VCR, TV, lights, telephone, pager, etcetera), a.k.a., the Green project. When that application was unsuccessful, the inventors proposed that it be used to implement video-on-demand (interactive television), a.k.a., the *7 (star seven) project. When that did not work out, Java found its current widespread application as a way to add active content to the World Wide Web.
It is valuable to think out loud about the full range of potential applications of an invention as early as possible in the development process. It is not necessary to nail down each potential application, but at least the order of magnitude of the number of applications should be divined early on.