As I see it, credit card debt is unsecured debt. Typically a credit card, for an "average" person with "average" credit runs in the vicinity of 18-21%. An auto loan is a secured loan, meaning you pledge your car as collateral, to "secure" the debt. Therefore, you get a 2-8% annual rate, due to the fact that you have good credit, and have pledged collateral to "secure" the typical auto loan.
That rate of 20% for credit card debt sounds pretty reasonable (not that I'd ever go there) for folks that can't find financing anywhere else. That's actually a pretty durn low rate compared to the typical "buy here - pay here" used car lot. I suspect Elio would make a couple or 3% for arranging the financing, so it's a win/win for them. They get to sell an autocycle, to someone who couldn't afford it any other way, AND make a few extra $$$ by arranging the financing, just like current car dealers do.
Heck, if you borrow $$$ from a pawnshop, in the state of Georgia, you'll pay 25% PER MONTH!!!!