Nelson is right. A bunch of us have played around with designing our own human friendly geohash scheme.
If you divide earth up into 4m x 4m cells using something like the S2 projection, you can uniquely address these using phrases of 3 words drawn from a database just under 32,000 words. The S2 projection ensures that the words in the higher levels of the hierarchy will change quite slowly. In most local contexts there will be only a single commonly repeated word. In a small number of more exceptional points there'd be just 2 or 3 unique values in use. So in practice you could use longer addresses and a smaller dictionary if you liked. This is probably a good idea for ergonomic reasons, as we can pick a set of words that are readily translated between languages, weed out any that are overly similar, etc.
I never uploaded the code anywhere, and it's on a laptop that died, but I busted out a toy version of the above in an afternoon a couple years ago just for fun. I used 4 word addresses and a database of about 2,500 of the most common english words.
W3W's entire value proposition is that they should earn a global rent off the use of addresses vs the above. It's absurd. And they intentionally avoid hierarchical organization of the addresses specifically to make it necessary to use their app/service to look crap up, which makes their service hilariously worse than the scheme described above.
With an S2 style hierarchy people will intuitively begin to recognize the common words in their living area at each level, and can use them in conversation without even consulting software. This is completely impossible with W3W's scheme.
The problem isn't figuring out a good scheme. Most of the people on this forum can manage that in a couple hours. The problem is the same with all other standardization efforts: getting a critical mass of people who give enough of a crap to use the standard.
This is an area where Google could ship something in maps and it'd have a decent chance of adoption outside of it. If you work on maps consider pitching a more ergonomic version of plus codes.