CrunchBang Linux

Hi!
I'm somewhat of a newbie and I'm trying to learn how stuff works the old fashion trial-and-error way. Anyway my question is just concerning lxsession which is started in the autostart.sh script, why is it needed? When I comment it out I notice no difference, I thought it was dealing with stuff like shutdown, log out etc, but that is done by the openbox-logout python script and that is not affected by whether lxsession is running or not.

So my question is simply, what's the advantage of having lxsession running in the background?