The third-party seller never gets your address. They hand the package over to the delivery company with a code, the delivery company is the only one who knows what that code means. Japanese delivery companies already offer this service, since a lot of people don't like to publish their address.
This seems worse for that though, now they can track you better when you move and correlate with your identity better.
But they could look up your physical address and store and sell that easily as storing and selling your delivery address now.
The third-party seller never gets your address. They hand the package over to the delivery company with a code, the delivery company is the only one who knows what that code means. Japanese delivery companies already offer this service, since a lot of people don't like to publish their address.