They said when it was launched that one of the main uses they foresaw was for deliveries and service provision (electricity etc) in non-addressed places, such as slums, informal constructions and new developments. I'm not sure it necessarily ties in with government uses.
Yes, that too. I remember reading an article about how it was used to get more nomads to vote.
Having an address opens up all sorts of things for people. Having an efficient address even more so. Here in .NL, you could write my name on an envelope, with "1066EA 1, Netherlands" and it will get to me (that's not my home address). In the UK "Name, 10 CT2 7NT, UK" Is enough for an address. All that other stuff we put on an envelope is redundant cruft. The postcode + house number is all you need. Unfortunately this isn't the case of all countries. In Belgium 1200 is the postcode of all of Antwerp. Germany and France's post code system is similarly stupid.
Being able to use liability.ramming.chips or influence.eyeliner.nozzles as an address is amazingly efficient. Having a system for 57 TRILLION locations that fits in just 10MB, is a real achievement.
We've had other systems for global location, but they are all clunky as hell. WGS84 Lat/Long is in theory useful, but you then have 3 ways of writing it dd.dddddE, dd.dddddN, dd°mm'ssE dd°mm'ss'N dd°mm.mmmm E, dd°mm.mmmmm, and when it comes to route planning between them, it's kinda clunky as you're doing base 60 maths, and it's a pain due to circles. This is why UTM was invented. With UTM, the base unit is a meter, and you can use basic Pythagoras and trig to calculate the location between two points. But it's a compromise, and esp at the edge of each zone, things can get blurry. I had a custom printed map of an area of Norway made, and they printed a valid UTM grid over it, but it wasn't the ideal UTM grid, meaning that had I used that map to read off coordinates, I would have got a position upto 3-4km away. In an emergency that would be enough to send the SAR team to the wrong place. Positioning systems are hard. *REALLY* hard.
What3words is something that can be used and understood by average people who just want to be able to say their Yurt is at impartially.lists.scrambled.
It's also been used by things like the superbowl, and festivals. You've got some drunks in a stadium, how do you radio the location in? "Um, bottom end of corridor C, by the hotdog stand" or smoke.energetic.harmony.
Yes it relies on an app, I can't easily look at my paper map and give you a what3words address. But with the right tooling (there is an API), you can have things like your standard security grunt's radio just show on the screen the current location as a what3words address.
It's a 10MB data set, plus an algorithm It fits in all but the most basic of phones. You could even implement it on an Arduino if you manage your memory well...
J