Is your keyboard not working? Are you using a public computer and not want a keylogger to store your keystrokes? In either case, you want to be able to type without actually using the keyboard. This is something that can be easily done using i2type.
I am sure that not many people with a working keyboard has ever thought about screen typing programs, but most public computers use a keylogger. Also, almost all hacking is done by accessing those logs to retrieve passwords.
Cut out your chance for violation of privacy. Check out http://www.sciweavers.org/i2type for more information!