In doesn't defeat the purpose since you have to pay back the loan yourself

I think the worse effect of the bail loan system is that for anyone who doesn't have enough cash on hand to cover it now has to pay the loan fee (or sit in jail and miss work, etc). If your bail is $100K and you need to take out a loan for it, that's $10K out of pocket regardless of whether or not you're found guilty. I would guess that half the people in this thread could just pay it and walk, and for the other half it would be devastating.