Sure, that seems a good example, and brings up a point I didn't mention: practicality can be a very contextual quality.
Generally though I think it's fair to interpret any question of "why should I bother learning X" not as a statement that nothing should be learned unless there's a direct benefit, but instead as the question "what are the practical applications of X". I think most people here would agree that learning for learning's sake can be fruitful & rewarding, so there's no reason to assume otherwise in response so such a question.
I don't understand what you're saying. If the OP's question was "what are the practical applications of X", then obviously he didn't consider it that learning for the sake of learning is useful.
Some people don't like to learn just for the sake of learning. So, I find it reasonable for someone to want to know the practical applications of something.
Maybe they prefer to learn through building something. Maybe they're working on something and are interested to know if Prolog could help them with their project.
Why say the OP obviously didn't consider learning for learning's sake useful? I see nothing obvious there. Asking for practical applications does not logically preclude the OP also appreciating learning for learning's sake, and I see nothing else in their post to imply their stance on it one way or the other. As such I choose the more charitable interpretation.
Well, it's christmas. Although I'm an atheist, HN has put on its holiday suit and I don't feel like pressing this point any further. My apologies to the OP and to yourself, if my earlier comment sounded too curmudgeonly. I'm really the Grinch that stole Christmas, so don't mind me :)
Generally though I think it's fair to interpret any question of "why should I bother learning X" not as a statement that nothing should be learned unless there's a direct benefit, but instead as the question "what are the practical applications of X". I think most people here would agree that learning for learning's sake can be fruitful & rewarding, so there's no reason to assume otherwise in response so such a question.