I personally prefer to use a more up to date version, so i don't use the one from the repos, but im sure people who just want to have a simple install, or a stable release could benefit from this.
Well, it's extremely helpful if you want to make a Debian package that depends on Clojure. But for development work, a more unstable version would probably be better.
It works like this: you start developing now. By the time you cut through all the red tape, you got the HTML templates, the servers were installed, the solution validated and you can finally deploy it into production, the package will be the same version you started development with ;-)
Agree - appears to have been around since Jan 2009, but judging from all the problems people seem to be have getting a simple Clojure install up and running, it does not appear to be well known.