If you take the printed information at face value, you would also have to convert the 50 Hz power to 60 Hz, which is going to be much more complex than a simple transformer. Most devices rectify it anyway and don't care, but it would result in a decrease in charging current of 15% in Pentium100's proposed circuit, and an increase in ripple. I wouldn't expect such a big cap to be cheaper than a transformer either, but who knows.