this in itself is quite unusual/seem kinda not clever

because now you are exposing a "implementation detail" about how you deliver the mail now to people in a way which is hard to change (or at least high friction for the people living there). But you should be able to change your postal routs ad-hoc whenever needed.

At the same time you lose many of the "dual-use" benefits many other countries get from it.

Like often (outside of the US) "zip" codes:

- are used for mail disambiguation (in combination with city/region and street names)

- cover (very very very roughly) a similar amount of people

- hence can be used for polls, statistics etc. etc.

- and due to not being to narrow scoped disclosing your zip code doesn't feel like major privacy invasion, so you actually get data for polls where e.g. your customers are from by asking at the checkout if they are willing to tell you their zip code

- are often also used for all kinds of administrative area scoping (not all, e.g. not voting areas or zoning laws)

so the us using a collection of postal routs which kinda somewhat but not maps to boundary lines seem like a major lost opportunity

Census tracts are, but those don't align to addresses in any meaningful way.

How are we to improve our Zones if the Zone Improvement Plan (ZIP) Code is not readily available?