Agree that green hydrogen is still in its infancy but I don't think it can be considered a "black hole", it's a new technology which requires, as any novel technology not yet proven commercially, government investments for research and further development.
I believe it ties quite well with the build out of renewables, the necessary plan for renewables is to overprovision since it can fluctuate, energy storage is one way to use the excess production, and another is to further develop hydrogen technology to be better suited for industrial processes requiring natural gas.
Without government investment there won't be any private enterprise developing it, it's quite known that capitalism doesn't help in taking massive risks with not-yet-proven technology, it can work for scaling, and getting into economies of scale but before that I don't think it's a black hole to bet on the future of it. At some point it will be needed to be done, rather develop the technology early, and export it rather than wait until China does it anyway (because the USA will definitely not be the first mover in this space).