1337x.am is the newest 1337x mirror site and only gets about 70,000 visitors per month. The amount of traffic this proxy site generates is in part indicative of the speed and safety of the service. Of course, being a new mirror site means that few 1337x users would know about the alternative 1337x option, which could be a reason for low monthly hits.
Regardless, the main usage of 1337x.am is to allow 1337x users from the main domain to search for and download torrent files via a BitTorrent client. To use 1337x.am, users need to input the correct URL in the web browser’s URL bar and start downloading content as with the main 1337x domain.
The difference between 1337x.am and the main domain is not much since, ultimately, 1337x.am is a mirror site that aims to provide as close an experience to the original primary domain as possible. Even though the content, theme and user interface are the same, there is no Bitcoin donation address on the home page as in the case of the main 1337x domain.
The reason for 1337x.am’s existence is to act as a third or a fourth backup website for users who can’t access either the main domain or the main mirror site. Being a verified proxy site means 1337x.am wants to maintain the brand value of the 1337x service.