There can be other advantages to not torrenting from an IP address that is easily tied back to you.
Many seedbox operators are located in Europe. If the MPAA wants to chase after someone torrenting copyrighted material they have to send a cease and desist to a European company against a Canadian violating copyright laws (and whose copyright laws - US, Canada or Europe) or send a subpoena to ask them for logs matching user to IP address - and that assumes that they can identify a specific person with that username.
There is probably lower hanging fruit for the MPAA to go after...