I think the article you linked to makes it pretty clear that there are many potential problems with coir. And there is a wide variability in quality. I clicked through to the full text article, and I didn't see any reason to consider using coir. I haven't conducted any scientific studies, but many years ago I used coir in large containers and coco chips in growing orchids and seedlings. I wasn't happy with the coir because it made the runoff from large pots red. All my orchids and seedlings died in coco chips. I don't know what brand I used, but I heard from others that it hadn't been thoroughly cleaned of sea salt. I will never risk using coconut products again.