Advantage:
(1) Choice
Just like we have Windows, Linux, OSX, BSD, BeOS...it is a matter of freedom to choose.
(2) Portability
If you need a really space saving way to input text. A palm size numpad controled by one hand will help you save much space resource.
(3) Speed
Since the numpad is compact and square shaped, it allows both high speed numeric and alphabetic input if you have train you position memory sufficiently.
(4) Free, absolutely FREE
Free in terms of free of cost, free to modify, free to redistribute, free to add on new idea to make it perfect for everyone.Free as long as the Autohotkey is GNU GPL freely available to the world. I am longing for making it fully functional and I can work with the PC with just one palm size wireless numpad.