I heard lending out bitcoin will make our bitcoin to grow in pace as well as securely. But, we need to verify the borrower more thoroughly before deciding a borrower. Getting a salary in bitcoin would be a more secure option :-)
lending out bitcoins to people isn't as interesting as it looks. especially when altcoins are being used to secure the loan. what if the altcoin price of the coin that is being used as collateral is dropping with 50% and the one that took the loan defaults. that means the potential profit is gone and you lose a part of your bitcoins too.
I also read few posts that A+ graded members also didn't payback the loan so it is not a safe place to lend coins to unknow person without any proper collatral. I would suggest don't ever try to lend any one without collatral. This will make sure at least our coins are safe but may not be growing.
BTC Jam is just a breeding ground for scammers. Many will just build up confidence taking out smaller loans trying to get a good rating then as soon as they get a big amount they like they'll just scam.