At best, it's just a "maybe easier to remember than GPS coordinates" system -- but remembering GPS coordinates with this level of precision is not really an insurmountable problem. I know its hard to remember, but up until a decade or so ago, people used to remember dozens of phone numbers, which requires a similar level of memorization.
It doesn't make addresses any easier to find than GPS coordinates -- you pretty much need a GPS. It doesn't necessarily guarantee unique addresses -- you get a different address if you pick different points on the same building or property.
It doesn't encode any routing information. So you're a delivery company asked to deliver a package to 123 Wascally Wabbit. You can convert that to a GPS coordinate easily enough, sure. But then what? Which delivery truck do you put the package on out of which delivery center? You can easily compute which delivery center is physically closest to an address, but that doesn't tell you if there is a natural feature like a river or mountain between the two points. On the other hand, USPS addresses encode the routing information -- the third line is the name of the post office that the delivery vehicle for that address departs from.
It doesn't encode any navigation information. How do you get to the address once you're in the general area? Which road gets you there? If you're a helicopter or a drone or a crow, you can just fly straight to the GPS coordinates, sure. But if you're walking or driving, as most people will be, you've just re-invented the sport of orienteering. This is the problem 911 emergency addresses were intended to solve -- you have a street name and a number for every address, so if you need to find an address in a hurry, you just navigate to the street (which is an easy amount of local knowledge to learn), and then you have a linear ordering of addresses so that you know when you've passed the address you're looking for.
It doesn't encode any service area type information. You want to order a pizza -- does the parlor deliver to 123 Wascally Wabbit? You don't know, and neither do they. You call 911 for a fire truck or ambulance -- are you served by the Newtown fire department, or the Newburgh fire department? Again, your emergency services need to plot your address on a map and then figure out whose region you're in. They can't just say, "Oh, you're in Plymouth, a suburb of Newburgh," and route your call appropriately.
(Essentially) saying "just use (masked) GPS coordinates" may technically assign addresses to all of those billions of places which aren't on named roads in recognized municipalities, but it doesn't solve it usefully.
You can integrate third party services to do just that.
But how does this help the 4 billion people currently without addresses? Do you think there are rich geographical datasets in places without addresses?
Even in places like the US where you do have rich datasets, it is still enormously inconvenient to not be able to do anything without them. The advantage of 911 & USPS street addresses isn't that they're easy to remember, it's that they encode a lot of useful information into them. (And even then, they don't include all useful information -- you typically need to know some ill-defined political or social boundaries, like the name of a neighborhood, to find out if someone delivers to your area or what the rate is for a taxi.)