I think it's getting more and more common, quickly. The obvious inference is that people are using LLMs a lot and starting to mimic them, consciously or unconsciously. (Probably the latter: if people have weak internal models of how to write well, being around a lot of LLM text can probably influence them pretty quickly.)

This is unfortunate, because (and probably much to the article writer's chagrin), I am a fan of making use of the formatting tools available for a given platform. When convenient, I love using an em/en-dash. And, when I'm up for it, italicizing and bolding words to convey prosody. It just feels right.

Now, though, I may be dismissed as an LLM (probably as an older model that can't quite use them formatting tools effectively).