According to the article, the problem it is solving is generating small amounts of power inexpensively and reliably. It would power those LED lights which are used to allow people in developing countries to read at night.
You seem to think that this is a small-scale proof of concept even though there is no reason to think that this is anything but the full sized device.
He doesn't claim nor does it seem credible that there is a particular advantage to this technology on larger scales. Bearing friction, which he cites as a problem at the small scale, is not such a big issue for larger generators.
