How important is course work to SCs? More specifically, does auditing (say) half a dozen courses add any value to one's CV? Does it look bad to a SC if a job candidate specializes in X but hasn't taken a course with a prominent X specialist on X from his or her department? Auditing courses is fun and often helpful for developing one's own ideas, but I'm wondering whether my time is better spent elsewhere.
I could be wrong, by my guess is that auditing courses adds nothing of any value whatsoever to one's CV. At my Ph.D.-granting institution, there were literally no requirements of any kind involved in an audit--you didn't even have to show up. The seminars you actually take for a grade, and for which you must do the reading and the writing and participate in whatever other ways are required, don't count for much of anything on your CV--you wouldn't think that someone was prepared to teach an upper-division undergraduate course on ancient skepticism based on the fact that she'd taken a seminar in grad school (would you?)--and audits are worth even less.
So--and again, I could be wrong--but I would say that auditing a seminar here and there might be good for your personal edification, or good for your dissertation when the topic connects with your research somehow. And some people (and I include myself here) do well with a little added structure in their lives, and having a seminar or two to plan things around can really help them stay organized and on task. But as a line on the CV, I can't see how an audit would be worth anything at all.