Some code has an “area code concept” like area code of telephone number. If code is divided into area code first, then assign local code inside of it, people is getting familiar with area code, and usually do not use area code for regional or local usage. Even if code is long, as long as people already know area code and use code within same area, they only have to handle local code. This makes code shorter, practically.

Most code has a hierarchical area structure and very flexible, but does not give an area code concept clearly.
N-Code, LocaPoint, and LP-Address have an area code concept.