I love maps and I regularly use over 18 map and GPS apps on my phone. What3word doesn’t work with any of them although many of them accept coordinates in multiple forms, postcodes, Google plus codes and, of course, addresses.

Having just spent months translating the poor addresses of over 4000 National Trust properties in my home State into coordinates I find it annoying that anyone would think this is good. I also don’t like apparent advertising on Wikipedia.
The only good thing about what3words is that I don’t see it taking over world mapping systems…