I was trying to figure that out too, whether they're making money off the hardware or my data. I found their privacy policy but I am still unsure what they're going for https://onlycoin.com/privacy/

I really think hard about whether these services are really worth forking over that much of my personal data, and as cool as this product is I don't think it's worth it. If vast amounts of my personal data weren't at stake I'd pre-order for sure :(