I'm not saying all of LLMs writing quirks are naturally derived just this one. It's a bit like it's overuse of em-dashes, they're not common in general writing which is why it stood out, but they do show up a fair bit in other types like scientific writing. My wife, who's a chemistry PhD, has bemoaned the association to me that she liked using them in her writing for papers and now it looks like she's using an LLM.