One of the things I like about Reddit is that you could remove whatever you’ve posted as and when you want, at least on the surface level. I’d definitely want my username to not be visible once I’ve deleted my comments. Call me paranoid but I have a habit of deleting comments that reveal too much personal info (e.g. “I’m an abc working in xyz…” or “my abc is suffering from xyz…”) every once in a while but if a particular comment has already been quoted and replied by many then deleting it but still keeping my username would mean that people can still more or less guess the original content and trace it back to me.