>Many smaller towns internationally do not require an address line
Citation needed. I've sent mail all over the world, and the only place I've seen where you can get away with that is Ireland. It's actually famous for this. Unless you're talking about some really backwater developing nations, every nation I've sent mail to does require an address line of some kind. However, in the UK, there are a lot of funny-looking addresses in the more rural areas. They have an address line, but it's really just the name of some hamlet or house or something, then they give the name of some farther-away but larger town, and finally the name of some main town/city where the mail is first routed. But they also have a detailed postal code that can route things by itself. Out of reasonably-developed nations, Ireland is the one that really stands out for having an antiquated postal system, but it does seem to work fine for them. It's also different and more modern for addresses within Dublin, where they do have a (very short) postal code.
The only other place where I've seen a place where you don't need a street or house number is for addresses at Kibbutzes in Israel.
Citation needed. I've sent mail all over the world, and the only place I've seen where you can get away with that is Ireland. It's actually famous for this. Unless you're talking about some really backwater developing nations, every nation I've sent mail to does require an address line of some kind. However, in the UK, there are a lot of funny-looking addresses in the more rural areas. They have an address line, but it's really just the name of some hamlet or house or something, then they give the name of some farther-away but larger town, and finally the name of some main town/city where the mail is first routed. But they also have a detailed postal code that can route things by itself. Out of reasonably-developed nations, Ireland is the one that really stands out for having an antiquated postal system, but it does seem to work fine for them. It's also different and more modern for addresses within Dublin, where they do have a (very short) postal code.
The only other place where I've seen a place where you don't need a street or house number is for addresses at Kibbutzes in Israel.