Here's the kicker, once you're registered and logged in, it's not like the pages load any faster, in fact if you just had a 30 second wait it would be an improvement.
I think the reasoning is more people will register and login to avoid the 30 seconds wait, that's the theory anyway, my take is it discourages more then it encourages. Plus then you get all the "special notice" email. When I registered and used a different email so all the "buy this" and "vote republican" email gets ignored.