That sentence should have used a colon, not a semi-colon, IIANM.

The digital world churns; Twitter is not an arena known for reflection. Semicolons, then, are snottily elitist and shadily indirect.

The elitist snottiness is in assuming people live their lives on Twitter and the like. They don't.

the semicolon has been usurped by ... the Dash

Well, _maybe_ some authors use more dashes than they used to (I actually doubt that, but never mind) - but a dash is not a substitute for semicolon. Their semantics are too different for that to be possible, IMHO. Take the first sentence in this paragraph: You can't replace the dash there with a semicolon, as that would mean splitting the "maybe" and "but" clauses into separate, not-directly-related clauses; you just can't do that.

indicating a pause

Not just a pause; a semicolon is also a semantic distancing. Two phrases separated by a comma are really an inseparable part of the same idea idea; if you separate them by a semicolon, they can each stand in their own right.