I watched the link video as a lunch distraction from playing with AI. I can’t recall if I saw or read anything about the broader implications for dark matter.
Does dark matter clump up like normal matter? I thought it was a lot smoother so wouldn’t create waves of relevant size.
It ultimately depends on what particle the dark matter is made of. It’s been a long time since I did any dark matter work, but from memory heavier candidate particles are more capable of forming structure because they move more slowly.
I never ended up pursuing that as a research area, so I’d take what I’m saying with a grain of salt, I just did a small project for a professor once.
I’m not smart enough to answer your question. But I wouldn’t mind speculating a little myself on large galactic and even filament scales. I think we’re underestimating how invasive gravity can be on these galactic bodies. There might be far more supermassive black holes out there that seem to have extremely far reaching affects well beyond the galaxies they inhabit, and perhaps their reach, or “waves” not only travel incredibly far, but might be adding to the galactic influences we see on edges of galaxies, galaxy clusters and filament formations/rotations. 
