The point, as I see it, is that you can call numbers abroad at VoIP rate without the hassle of using a headset attached to a PC, i.e. as Skype users do, because it uses your POTS handset and line.
Admittedly, as ian@huth correctly pointed out, if you're having to open your browser on your PC to enter your details, then it does kinda negate the point of using their service as opposed to any other VoIP service.
I suppose if you're using a WAP-enabled phone then you could browse to their site and enter your details that way, and save on the normal charges applied to mobile phone calls
