I have used a dash - like that for almost 20 years, 100% of the time I ought to use a semi-colon and about half of the time for commas - it let's me just keep talking about things, the comma is harder pause. I've recently started seriously writing at a literary level, and I have fallen in love with the em dash - it has a fantastic function within established professional writing, where it is used often - its why the AI uses it so much.
I once spent a day debugging some data that came from an English doc written by someone in Japan that had been pasted into a system and caused problems. Turned out to be an en-dash issue that was basically invisible to the eye. No love for en-dash!
Compiler error while working on some ObjC. Nothing obviously wrong. Copy-pasted the line, same thing on the copy. Typed it out again, no issue with the re-typed version. Put the error version and the ok version next to each other, apparently identical.
I ended up discovering I'd accidentally lent on the option key while pressing the "-"; Monospace font, Xcode, m-dash and minus looked identical.
Em dashes used as parenthetical dividers, and en dashes when used as word joiners, are usually set continuous with the text. However, such a dash can optionally be surrounded with a hair space, U+200A, or thin space, U+2009 or HTML named entities   and   These spaces are much thinner than a normal space (except in a monospaced (non-proportional) font), with the hair space in particular being the thinnest of horizontal whitespace characters.
1. (letterpress typography) A piece of metal type used to create the narrowest space.
2. (typography, US) The narrowest space appearing between letters and punctuation.
Now I'd like to see how the metal type looks like, but ehm... it's difficult googling it.
Also a whole collection of space types and what they're called in other languages.
In German you use en-dashes with spaces, whereas in English it’s em-dashes without spaces. Some people dislike em-dashes in English though and use en-dashes with spaces as well.
In English, typically em-dashes are set without spaces or with thin spaces when used to separate appositives/parentheticals (though that style isn't universal even in professional print, there are places that aet them open, and en-dashes set open can also be used in this role); when representating an interruption, they generally have no space before but frequently have space following. And other uses have other patterns.
In British English en-dashes with spaces is more common than em-dashes without spaces, I think, but I don't have any data for that, just a general impression.
Double hyphen is replaced in some software with an en-dash (and in those, a triple hyphen is often replaced with an em-dash), and in some with an em-dash; its usually used (other than as input to one of those pieces of software) in places where an em-dash would be appropriate, but in contexts where both an em-dash set closed and an en-dash set open might be used, it is often set open.
So, it’s not unambiguously s substitute for either is essentially its own punctuation mark used in ASCII-only environments with some influence from both the use of em-dashed and that of en-dashes in more formal environments.
Apparently, it's not only em-dash that's distinctive. I've went through comments of the leader, and spot he also uses the backtick "’" instead of the apostrophe.
https://www.gally.net/miscellaneous/hn-em-dash-user-leaderbo...