Well, discoveries and inventions usually find their use WAY outside their intended use.
Think about this, Galileo, who worked in a glasses shop, is considered as one of the early known inventor of compound microscope. Now by the same token, what is the use of seeing really small objects like cells. Or very small living creatures like amoeba etc? During the time of Galileo, microbes model of disease was not fully formed. People suspected something living might be causing some diseases but no one knew what it was. These were all conjectures. Heck, this theory was not fully proved till 18XX by Louise Pasture. Compound Microscope or magnification by multiple lens could only have very limited use. For instance in watch making. Studying microbes itself was not as useful.
It was only later when people linked microbes and disease (as in 18XX by Louise Pasture), study of small organisms had a lifesaving impact.
Did Galileo knew or INTENDED that his discovery will have a life saving use? Did those who studied very small microbes knew the impact of their work on microbes? Perhaps a bit, but arguably not as much. Only after Louise Pasture formulated his theory of microbes causing disease, these entire pieces started to snap and fit into complete puzzle and we now have a life saving science called modern medical field.
Science and technology has a lot of chance in it. Its not something you can completely plan out and execute in a top down manner. Thats why each nation should spend a part of their revenue in pursuit of science and technology. Even if you spend that money on more seemingly practical use, it is likely that you won't have as much value in present as you might have in future -- many times simply accidentally.