I've actually owned that phone. It really, really does not work well, even for just calls. My battery life when using it was atrocious. Also, send/receiving texts was a very difficult task.
Agreed. The battery life was surprisingly short, given the epaper screen and the lack of any features. The UI was a product of a completely deranged mind. The only way to get to some really common settings is to press dozens of random buttons, like game cheat codes. It doesn't even have the ability to sync the clock from the phone network, so I constantly had to reset the clock (!). The idea is good, but the implementation sucks badly in every single dimension.