Many don't realise that What3words is actually completely proprietary which means it's a bad idea for governments and others to adopt as a standard as at any time it can be changed, licensed with charges, or just disappear.
The Open Location Code (OLC or Plus Codes) is a geocode system for identifying an area anywhere on the Earth. It was developed at Google's Zürich engineering office, and the algorithm is licensed under the Apache License 2.0. and available on GitHub. It is also integrated into Google Maps, but anyone can freely integrate it into what they are developing. There is no backend server or service needed to use these codes.
There are many communities on Earth still which do not have a formal addressing system, nor even postal codes. Creating addresses for a whole town or village could take years. But with the Address Maker, it only takes a few weeks to get under-addressed communities on the map. Address Maker is already being used by governments and NGOs in India, Kenya, The Gambia, South Africa, and the US, “with more partners on the way.”
See Google's new Address Maker makes it easier to create new addresses
Address Maker is a free service that helps governments and NGOs easily create new addresses for under-addressed communities.