Well, I may not eligible for $500 short term loan on a typical credit underwriting. If I goes offline, my credit score is not that great. If I go typical bitcointalk, my account is not that established for a collateral fee loan.
The process in my mind was little different. The lender pay me $500 through PayPal, I will issue a refund within 10 days. I will be sending the interest as eth/ btc. The lenders capital is protected with PayPal. He won't loss a single penny even in waste case. I will be paying a decent amount as interest for the hassle.
I have worked on credit underwriting tech for sometime. From my understanding, the lender is only risking his interest. Could you share your point of view?
I thought you want it the other way around and i misunderstood it, so my apologies for my previous post.

As zazarb state, this is a deal safe enough for the lender.
Nevertheless, from my point of view, PP isn't the best way to deal when it comes to loans...