If you want to watch (say) a German movie in German while in America, you need to import a DVD player set for the correct region. This is certainly possible and lots of ex-pats do it, but it's not as simple as "just buy the DVD."
The hard part is to get the movie, compare it to Netflix, right? If you already got the DVD, it's physically yours.
The hard part is to get a DVD player that will actually play the movie. You can't walk into Best Buy in Iowa and get a European region-coded DVD player.
Region-free (all-region) DVD players are a thing, and they are pretty easy to find.