I think it depends on the situation and circumstance. If you are selling food and you have a certain neighbor so hungry, it will be inhuman of us if disallow the hungry neighbor to buy in credit. But if it always happens and no single payment is made, that neighbor needs discipline by refusing to purchase food on credit. For a big sore, unless that customer already built good friendly relations, a good creditor, no reason to refuse, so it is case to case. What about your observation in your community?
I think that credit could be good for business because this helps you to secure more and more clients in the first place. This makes it feel that you trust your clients.