In fact, quite essential when seeing incoming links to old URLs in your Webmaster Tools account or Analytics overview.
Allowing regular expression in the redirection rules makes it easy to manage moving a site or switching multi-language plugins for example... Plus excellent logging of traffic (including referrer!) of all that passes the new rules you set or any 404s occuring on your site.
A valuable asset to anyone that cares about how visitors navigate on his/her site and about SEO in general. Five out of five stars with full conviction! :)