Gates argues that technological advances become economically important when they are paired with applications that provide clear and compelling value. A new technology may initially attract attention because it is novel, but widespread adoption often depends on practical uses that make people or organisations willing to spend money on it.

The phrase “killer application” refers to a use so valuable that it helps drive demand for the underlying technology itself. In personal computing, applications such as spreadsheets and word processors helped turn computers from specialist tools into widely used business products. Gates’s point is therefore about the relationship between invention and commercial adoption: technical capability alone does not guarantee a market. The quote can be applied when assessing emerging technologies, where the decisive question may be whether developers can create applications that solve important problems and justify the cost of adopting the broader platform.