I have experimented with this, so that I can post some outrageous stuff and see if it flies. Or post some stuff that's just too personal to put under my actual name. Unfortunately, I don't really feel it works very well because my second account has no readers. No one cares if my stories are outrageous. And because a big part of Medium is the social interaction, it doesn't really work so well - you need to double your social efforts. I'm already exhausted. But you know, it's there, if I have something outrageous to say that's so politically incorrect that I daren't post it under my own name.

Also, I still feel constrained by my own sense of what's acceptable. And what might get me shot down. So it's not very outrageous.