Some important context - Zip codes were not established as geographic markets. A "Zip Code" is collection of routes USPS uses - so it's whole goal was to get the right package on the right truck.

The "Zip+4" was the attempt to solve this- the 9 digit code narrows down the zipcode to a single block. But no one in the US cares enough to use these. It also doesn't solve the canonical problems the industry has with mapping data - people want to be able to put a pin in a random place on the map and pull up a clean zip code for data processing reasons.