Some users don't get multiple speed single downloads. It takes them the same amount of time to download something when the network is otherwise quiet, unless you are considering the situation where the network is being heavily loaded by multiple users or multiple downloads all going at the same time.
Their kit can have devices with two or more addresses assigned to them simultaneously, one per line, and a machine can get multiple simultaneous streams of stuff inbound to each one of the addresses. The Internet knows there are n lines and has to choose somehow which IP address (for which line) it's going to send stuff to.
In contrast, my router and the machines on my network don't have three IP addresses one per line. They just have addresses that are associated with the entire group of lines, and the internet knows nothing about the three lines. The load splitting over my three lines is handled by the ISP for inbound traffic, and by the router for outbound traffic.
