In this example they are checking out into a work tree that is detached from the central repo, which is bare (or could be.) Therefore there is no .git directory

In this example they are checking out into a work tree that is detached from the central repo, which is bare (or could be.) Therefore there is no .git directory in the work tree and the history is inaccessible from the outside world. I don't see how having the entire history sitting in a private directory on the server is silly, as long as only you can access it. Honestly we are just talking about transferring files here. However you automate it, as long as it gets the files from point a from point b, is fine. I happen to find it most convenient to use git since that is how I send and receive code changes everywhere else, and it seems foolhardy to introduce another file transferring tool without a really good reason why. Moreover it lets me very easily tell exactly what revision is sitting on the server, and also causes me to pause before I push. It is also really easy to integrate git, through hooks, with a continuous integration setup.