I think there are platforms like this in the US as well.
We have them, like
http://www.prosper.com/ , but I don't find their rates to be competitive. They aren't even competitive to credit cards.
Edit but I agree bitcoin lenders are unrealistic with their APRs. The other side of it, though, is that there are so many borrowing scams that it's not worth it to offer a low APR.
, their rates are very good if you have good credit.