Yes, while we sometimes do pursue scientific inquiry for its practical application to the betterment of humanity, we also recognize the value of scientific inquiry simply for expanding the endowment of human knowledge about the world. That is an "innate good". Moreover, if history is any guide, it's sometimes or even often difficult to predict what practical applications will or won't emerge from any given scientific endeavor. In the case of Dark Matter, it may not be exactly the case that we will ever directly manipulate it in any scientific application. However, it may be the case that by grappling with Dark Matter we will refine and deepen our understanding of the fundamental laws of nature, and that will unlock future practical applications. Then there is the topic of "human capital": training people to be scientists trains cadres of people with strong skills in science, math, engineering, and computer science, which is an investment in that human capital. Often, they're well-equipped to go on to fruitful careers outside of their initial field of inquiry, producing innovations that benefit humanity. Finally, if it's a matter of cost, many people feel that the societal cost (e.g. federal expenditures on science) are puny compared to other things which I need not name here. Consequently, "basic science" which includes fundamental physics and the study of Dark Matter, is always a great investment for society.
Or something like that...that's my understanding of how that argument goes. Make of it what you will.
Superconductivity is absurd magic and took impossibly low temperatures until they weren't impossible, and now it's driving MRIs, massively improving medical research, and the realm of usability is constantly expanding. Absolute zero was known reasonably accurately for over 100 years before liquid helium was achieved, and superconductivity came only three years after.
It's the kind of thing you can frequently only judge accurately in retrospect.
My guess? If we figure out how to detect dark matter we can get closer to figuring out how to interact with it (other than through the very very very weak gravitational force). Or maybe we figure out that it was a spinning universal frame or something that gives us a better Standard Model.
If, however, we figure out how to interact with it and can harness any potential energy from it, then by definition we won't see any interference in the electromagnetic forces. That would be incredible, that would be as good as having readily available superconductors.
https://www.energy.gov/science/doe-explainsquantum-mechanics
> Quantum mechanics led to the development of things like lasers, light-emitting diodes, transistors, medical imaging, electron microscopes, and a host of other modern devices.
Additionally, it's ironic that you mentioned the Higgs-Boson, while perhaps many years before it's discovery and maybe not research CERN was anticipating in doing it did come up with the first webserver:
https://home.cern/science/computing/birth-web/short-history-...
It was only years after his death that Parsons would use his work to determine the necessary geometry of the rotors and stators in his new and revolutionary engine. Regnault certainly didn't see that coming, the people who overlooked his work didn't either, but that pure science for the sake of science helped to change the world.
So as you say, we often don't realize what we're going to do with the results of pure science until engineering catches up, sometimes decades or centuries later. Still without the pure science we'd never get the engineering.