Steve Coast, OpenStreetMap founder and what3words employee on why what3words is a good thing: https://stevecoast.com/2016/03/25/why-i-like-what3words/
Conversely, (as another HN user pointed out), OpenStreetMap's opinion of what3words is quite negative: "what3words is a commercial, non-open, patented location reference schema. Open data advocates (such as the OpenStreetMap community) would generally advise against adopting it at all."[1]