I thought the same thing, but on further inspection its pretty crap-tastic.
The battery life is two years, with no way to change it, so you have to buy a new coin and then reenter all your info.

That breaks down to paying $50 a year at the full retail price (currently). $50 a year would probably be a little more palatable. The idea was great, execution poor - though if it takes off they will make money as every two years there is a product refresh.