Actually, Irving Berlin had an amazing sensitivity to the idiomatic scansion of American spoken language, and a lot of his earlier work uses the slang, phrasing, and rhythm of the various ethnic groups, including the characteristic Yiddish left dislocation.

As to "White Christmas", it's a song about peace, and far better known, and more remembered than most of the traditional ballads we like to fuss about.

And Morwen, here in the US at least, we all know what a "Berlin Ballad" is...