I gave my employees a pay advance and deduct partial repayments from their future checks until paid off
That's considerate, but why do you feel you need to do that? Were they struggling?
They are very poor financial decision makers
That's very understanding of you to do that. However, you're going to leave yourself open to people sometimes not paying you back. I'd be ready to get taken advantage of by some of these employees of yours from time to time.
That's a gamble I'm willing to take. It's a bit risky but I expect most people to be honest with me.
It's definitely very noble of you to let employees borrow money in this manner as long as you understand there's a risk. I think you're doing a great thing.