zlacker

>>voxada+(OP)
ZIP codes are an emergent property of the mail delivery system. While the author might consider this a bad thing, this makes them "good enough" on multiple axes in practice. They tend to be:

- Well-known (everybody knows their zip code)

- Easily extracted (they're part of every address, no geocoding required)

- Uniform-enough (not perfect, but in most cases close)

- Granular-enough

- Contiguous-enough by travel time

Notably, the alternatives the author proposes all fail on one or more of these:

- Census units: almost nobody knows what census tract they live in, and it can be non-trivial to map from address to tract

- Spatial cells: uneven distribution of population, and arbitrary division of space (boundaries pass right through buildings), and definitely nobody knows what S2 or H3 cell they live in.

- Address: this option doesn't even make sense. Yes, you can geocode addresses, but you still need to aggregate by something.

>>jonas2+Xd
One more advantage: ZIP codes are a good trade-off if you want to gather anonymous data in a survey or provide anonymized data to an outside entity. For example, we recently conducted a survey on mobility patterns within our university. To offer respondents a reasonable amount of anonymity, we just asked for their (German) ZIP code and the location of their primary workplace. This allows us to determine the distance and approximate route people would take between home and university campus - to a degree that is sufficient for our goals.