What I got to think recently about the value of knowing more about stuff whose usage isn't imminently obvious is that when you expand your knwoledge, the 'range' of your world changes. So yes, almost by its nature, you would not use the stuff that you don't know much of, but you would be hemmed in by your own ignorance. On the other hand, by expanding your knowledge, you would also expand your range of experience (your world) thus find it more useful.