There are situations where it's useful to use a real name; it's come up for me in directly programming-related projects, where having my name attached to commits is useful for resume purposes, and having the same name attached to the commits as the comments gets one taken seriously. And if I ever am getting a game published, naturally I'll want to promote it using my real name on BoardGameGeek, etc.

But even then, separating the various personae into different identity chains is useful.