The Universal Serial Bus (USB) is a widely used bus connection standard, mainly due to its simplicity, low cost, and wide adoption. Many IO devices support USB, and the “plug-and-play” nature of its operation helps user convenience.
USB 3.0 supports high speed requirements (up to 5 Gbits/second).
Generally the USB protocol is pretty difficult to properly implement on the digital hardware level (especially compared to the PS2 protocol).