The most convincing use case (for plus codes, not w3w but same logic) I've seen is that it can be used instead of an address in slums and similar places where addresses aren't available/practical

The problem is that it's useless without a phone but if you have access to a phone then a gps location is better, unless you have to remember it or put it in by hand

The UK has had a bunch of news stories about using the app, as it "could save your life". For example:

https://www.bbc.com/news/uk-england-49319760

But if you need internet access anyway I'm sure that GPS would be a better thing to use, and there are also stories about the use being questioned for accuracy reasons:

https://www.bbc.com/news/technology-57156797

Really though I think it's a cute hack to use such a small number of words to define points - but as a closed source, and sue-happy company, there's really nothign to recommend it. Sure the average Joe might not be familiar with reading/writing GPS coordinates, but over a phone I'm sure an emergency dispatcher could walk them through it.

I'll try my best attempt at a steel man: It can be a useful way to convey location information via language (spoken or written word), when there isn't a direct digital connection between sources. That's genuinely a non-negligible use case.

So if you see an advertisement for a restaurant at giant.purple.monkey, you can get there. Or maybe you're coordinating plans on a non-smartphone call. Or you could put the location on flyers (a QR code could work, but lots of people hate those). Or you're dictating a location to a smart assistant (Mercedes-Benz did a partnership, and AFAIK the in-car assistant accepts W3W locations; I don't know for sure though, I use android auto in mine; disclaimer: I work at MB).

In practice there are problems with plurals, homophones, and other similar pronunciations (did he say heavy.monkey.dress (near SF) or heavy.monkeys.dress (near LA)). I think realistically W3W is almost never the best option, but I do quite like the idea. Maybe if they did a better job filtering words to avoid collisions, and made it 4 words? I imagine it could actually be a pretty memorable way to describe a location if it were something like adjective.noun.adjective.noun, and with fewer near-collisions in the library (heavy/heady).

I've read about some Native American tribes using Plus Codes as street addresses for homes on their reservations for the purpose of issuing IDs so their residents can vote.[0] They had not previously numbered their homes and the bureaucracy to register the home numbers might cause voters to miss the election deadline.

[0] https://www.sltrib.com/news/2019/10/06/some-native-americans...

Part of the reason, or at least a reason for a gap in the market that this could establish itself in, was that some countries who had built there own (quasi-)equivalents were similarly protective of their "intellectual property" and trying to charge for or just being awkward when providing geolocation data.

https://longair.net/blog/2021/08/23/open-data-gb-postcode-un...

I'm from NZ which has logical addressing. Trying to find some random business on some random shed, down some random lane in the middle of nowhere in the UK can be quite the challenge - post codes don't help and "turn left at the white post, go down the lane till you get to a crow that's staring south, then drive up past the.... " directions are terrible. What3Words has been great for finding those places that use it... easier than writing down a GPS co-ordinate.

Money (for w3w)

For everyone else: No.

It’s very lucrative for a few investors and public funds never run out.