Check out the input method list on whatever OSs you use, and I expect you'll see multiple Chinese input methods. OS X 10.8 has 10, Windows 7 has dozens, a quick Google search shows that Ubuntu 12 around 13.

It turns out that, with over a billion people and dozens of dialects, many different writing styles, and a long history of different electronic input methods, Chinese speakers really do need multiple different ways of inputing Chinese.