They certainly have their place, but are massively overused in contemporary American prose. This might be slight more of an east coast thing, but that's just a subjective impression that I'm not willing to spend time measuring.

To me they come off as faddish, with many writers using them where commas and semicolons would have done just as well. I think their popularity stems from teh fact that provide the sense of a personal aside from the writer, allowing them to be more expressive while clearly delineating the personal or contextual remark from the main flow of the prose. No doubt this works for a lot of readers, but I find it tedious.

It's a fad that has been going strong for centuries in published literature, so I'd guess an awful lot of authors world disagree with you.

You can restructureany sentence to use fewer forms of punctuation -- but if you do that, you'll lose nuance. And nuance, in writing, is a very fine thing.

I use them because I know what I want to say out loud, but transcribing the pause with commas is incorrect because it's a comma splice, and I find that the semicolon often looks glaringly overly formal. So I've settled on the em-dash.