Put yourself in the other mans Boots. They are investors. The interest rate has been at an all-time low for years and doesn't look like it will increase for a while. So. Choice 1 is to keep all your dollar in a savings account and see it doing naff all, Choice 2 is to take a fairly safe gamble and lend it to people who can't afford it. Afterall, if you are investing millions in a loan scheme, you would be taking out insurance policies to safeguard your investment.
I was the prime example of an idiot in my early 20's. Bought a house, wandered into Land Of Leather and spent £4k on a Leather suite which was interest free for 4 years. No payment required for 12 months and zero deposit. I'll leave you to guess how that panned out! In fact, no I won't.... I'll tell you. I'm sat on it now, and I haven't paid a penny for it.
Credit is a bad thing - unless your current account is in credit - and that's a good thing.