You want to make a phone call to a person, who is number 50 down in your list? Open Contacts and you have a choice: either you push the joystick down 50 times, or you must open the keypad and type the first letters of her name. Not so if Soft Keypad is ready in the background: press the joystick twice quickly and a virtual keyboard pops up, where you can "type" the letters with a minimal number of joystick actions... Same thing in the Phone application, where you can dial a full number and make a call, without your thumb leaving the joystick at any time!
Soft Keypad supports normal text input, predictive text input (T9) and numbers input: in most situations, it will detect the input mode of the application in the background and pop up the virtual keyboard suited to the situation. You can even switch the input mode of the device from normal text to predictive text and back with an Options command of Soft Keypad.