More generally than editor support, how is the average person expected to type them? I could easily add them to my keyboard, but if "editor support" turned out to mean "Edit > Insert > Record Separator Character" and I was now bound only to editors that support this, absolutely nobody is going to bother. They specifically need to be trivially typable in exactly the way commas and newlines are.
Realistically I don't think anyone (at least on HN) would presume that editor support would be so weirdly obtuse, but it's not exactly well-defined here, either.
I'm mostly just thinking out loud, here, not really critiquing anyone.