I think there's quite a lot of value in impractical, disconnected-from-reality, argumentation.
I read an article this week which made the point that academic philosophy is not valuable because it's so disconnected from reality. The specific section I'm talking about says:
I will never forget I was sitting in our auditorium listening to a long talk about meta-ethics when right outside the doors of the university auditorium Black Lives Matters activists were marching (this was in St. Louis at the time of Ferguson)... I could hear them chanting — the stark contrast between the esoteric subtleties of meta-ethics vs the concrete realities of what would be considered “applied ethics” (a term usually uttered with slight contempt) made me deeply uncomfortable.
This is a hard-hitting image. That there is such a disconnect between the real issues we have today and the group that purports to be doing ethics should make you deeply uncomfortable.
However, I don't think this is a straight apples-to-apples comparison. The activities going on in the classroom should be thought of more as training in how to think. By grappling with ideas that are abstract and disconnected, we remove our gut reactions from our evaluation. We're able to think clearly because we don't really care about whether or not (to use the article's example)
modal realists from different possible worlds can fall in love with each other. Thinking this issue through and taking a side is an exercise in pure argumentation. In that way, it serves as argumentative weight lifting. There's no practical purpose to the results - the exercise itself is where the value is. Students' minds are being strengthened. This is good in and of itself - people should be their best selves - but it also leaves them better prepared to deal with the many shades of gray in everyday ethical issues.
The other issue the author cites - the lack of good tenure-track jobs - I'd argue is a result of how widespread the author's first viewpoint is. There's a general devaluing of philosophy for its own sake, testing and improving the ability of the human mind to approach difficult problems and make difficult decisions, which stems from the idea that it's so disconnected from reality and results in a lack of respect for the profession. Clearly, publishing more impractical philosophy won't make people respect it more. Perhaps the field needs to produce more well-argued practical papers. Papers like that would be subject to intense scrutiny - and intense backlash, if they were on such hot-button topics as the Black Lives Matter movement. So it's important that the philosopher who undertakes to write such a paper be well versed in how to write and how to argue. The exercise of impractical philosophy serves as a training and proving ground for those skills.
So I'd say impractical philosophy has value at least as a training ground for thinking about topics that are more difficult to approach. It improves the ability of the student to write and to argue from reason, as opposed to from gut feelings, and prepares them to write about practical issues that raise strong emotions.
Did I miss something? Do you think there's more value (or less value) than I've proposed here? Let me know in the comments.