This question is a result of seeing a headline about Mercedes Benz adding What2Words to its in-dash navigation system. I think I understand what What3Words is about but I can't help but feel I'm missing something about how & why I'd want to use it.
In a nutshell, it places a roughly 3m x 3m grid over the planet. Each "square" is given a three word identifier. I give people the three words as my location. Great! Now that we have a basic understanding, let's meet for pizza and beer at whiskey.tango.foxtrot around 6pm.
Without using a computer, how do I find whiskey.tango.foxtrot? A street address (123 main street, anytown, USA) doesn't require any electronic tech and it even works when the power grid goes down. If I'm across the city but on the same street, I can look at the numbers and just walk. I might be 50 yards from cat.dog.chicken but how does that relate to my current position of donkey.cat.moose? I know that 250 main street, anytown, USA is fairly close to 123 main street.
A latitude / longitude coordinate pair gives me absolute location and I can estimate distance between multiple pairs. Think maps, sextants, stars, etc - you can locate yourself on the globe. Think USGS topo quad sheets. Latitude increase as you move away from the equator. Longitude increase as you move away from the Prime Meridian.
W3W seems to use a proprietary algorithm and requires using its service to decode W3W. You don't know what word is adjacent to another word and unlike lat/lon, you cannot determine direction from two words.
I understand W3W is easier to remember than addresses or coordinates but, in my opinion, the wheels quickly fall off when the technology (internet connectivity, cell service, electricity, a computer) is taken away.
I've considered using W3W on a project but determined the ease of remembering it -seemingly a huge selling point - was outweighed by actually being able to use the values.