Actually, the dateline is far more important than that. I didn't always know this, but the dateline is actually a contract telling you where the reporter was in person, and is the difference between the "hard" journalism of yesteryear and the "soft" web journalism of today.
Read this investigation [0] by the NY Times into the story of Jayson Blair, whom they fired after discovering he was faking sources for his articles. It talks a lot about journalistic integrity and was the first time I learned that datelines weren't just where the article happened but also the journalist giving you their word that they were there, on the ground.
Once you learn this, you start to see it everywhere. For instance, a recent article about the deep freeze we had here in Chicago (we hit around minus 50 degrees F with windchill for a couple of days) talked almost exclusively about Chicago, a little bit about the Midwest in general, and a single sentence towards the end about Michigan. The byline? Detroit, MI. Now you know why!
[0]: https://www.nytimes.com/2003/05/11/national/times-reporter-w...