All my bills are sent to them, they photocopy them and put them online for me to see. Click-click. I pay my bill, they either mail a check or EFT the cash to the biller. My real (brick and mortar) bank account is automatically balanced accordingly.
I have had this service for several years and never had a problem. What makes them different from most bank bill paying systems is that you don’t ever have to go to the mailbox. One drawback is that the address that your credit card recognizes is this bill payment address (your private PO box in South Dakota). So, whenever you use your credit cards and are asked what your address is, you have to remember to use this address. But, because of this system, you don’t get a bunch of junk mail and it makes it almost impossible for someone to make a large (or online) purchase on your credit card unless they know your billing address.
Most big banks have online banking that works very well too, but I don’t like their bill payment services.