I have lived at a non-delivery address for the past 5 years. The “every address” myth seems to be propagated by people who support USPS and conflate “we deliver to people all over the US” with “every address”.

That sounds similar, but is significantly different, and can be a major pain when dealing with people or businesses that believe the myth, and try to send important paperwork to a physical address, which may end up in our P.o. box if the USPS person handling it recognizes the name and can match it to a box number.

Putting both the physical and P.o. box addresses into an address block, in that order, works well, but then shippers can balk at finding a box number. (see also “Falsehoods programmers believe about addresses, etc.”)