The dictionary doesn't quite do justice to the word 'boondoggle' according to author Dmitri Orlov, best known for his book Reinventing Collapse. A contemporary boondoggle must not only be wasteful, it should, if possible, also create additional problems that can only be addressed by yet more boondoggles. This does NOT preclude boondoggles from being profitable for certain insiders.
It's important for these investors NOT to understand the economics of mining. If they did, they would be investing in terrestrial mining operations or some other sector of the earthbound economy instead of the boondoggle of asteroid mining. Such mining assumes that the costs of extracting earthbound mineral deposits will rise sufficiently to match the cost of asteroid mining, thereby making asteroid mining competitive.