It’s bad in so many ways.
Primarily it’s just a commercial business being touted as a brilliant way to save lives. They have a massive PR campaign running. Analysis shows many problems.
You need their app and it and the data is not open.
The words are not chosen to sound different, they have used plurals and homophones.
Neighbouring places have vastly different names, you cannot tell if 2 locations are near to each other.
The words are not neutral between languages.
If you want to give a W3W location in your app website, you have to use their system to get the references, you cannot use your own version.
My favourite clone was WhatThreeF**ks which used swear words for location.
The biggest clone which was available with an explanation of the algorithm was WhatFreeWords. But due to the aggressive lawyers involved, the authors never revealed their ID and like all competing systems has been taken off line. It’s still available if you know where to look but you wont find it with Google. Of course, if W3W was not purely a commercial venture but a real way to save lives, this perfect clone would not have been driven off the web.