If you had ever compiled some of these datasets you would realize that it was impossible to get the datasets without extremely complicated scrappers that generated jobs, waited for a tiny little portion to be extracted (like 0.1% of it), and download the result from an ftp location that had non-standardized names... or how you would end up just giving up, calling people on the phone to ultimately get the person in charge to return the call to you, and buy pre-filled HDs from them that would get mailed to you eventually.

This is far more than a glorified mirror.