That is a complete misquote. For applications that
inovle large data
 transfers nad where there are no real-time requirements, such as
 interfacing to removable flash memory, external disk drives, and the
 like, I think that USB is possbily the right itnerface to use (There are
 others too...). But that doesnt' mean I think it's the right interface
 for all peripherals. 
    Easy question:
    USB is a high-speed interface. It is already there, so why NOT use it
for keyboard and mouse?
    Once developed the controller, it just works, you don't need to do it
again, and it sells at millions. Why not? :)