I still call voodoo on this. I use an iPhone, iPad, Mac to comment here—all of them autocorrect to em dashes at one point or another. Same goes for ellipsis.
You can remove em dashes from the analysis and the trend is still there: newly created accounts are still 6X more likely to use the remaining LLM indicators (arrows and bullets, p = 0.00027).
Ellipses were never part of the analysis.
Why would recently created accounts be 10x more likely to be created by owners of Apple products or English majors than the baseline?