Why? Well, because there were some patterns my fellow sewist-bloggers/patternreview.com-users had problems with and then blogged about.
So when that next great pattern sale comes up you can get off your butt and to a store to get that pattern you keep thinking about but have not bought yet before it disappears forever (or makes itself very hard to come by).
Every time I have to look at that Simplicity site, I realize what a great job these guys have done, probably in part because they were able to learn from the mistakes that the Simplicity Creative Group made. I wouldn't be surprised if they didn't just Google and find links to sewing blogs complaining about Simplicity's new interface and worked from there.
Good job, McCall Patterns!!!