In the Matrix we were batteries.
The interesting part of this technology is the power. Could it work on the surface of the skin? Imagine charging your gadgets by having lunch.
I have a high doubt-quotient about cel phones and brain cancer, but what if it turned out to be true? Can you imagine the tumors these things would cause? At least your cel phone isn't actually connected to your head.
Breast implants seemed like a good idea to a lot of people at first too.