It can be used for employers, but it's not limited to that. It can be any sort of business, or financial institution. Nothing is stopping Epoch or CCBill from offering this convenience to their customers. I believe their only reason is that it gives them less of an opportunity to charge for sending money. And in the case of ACH, virtually no chance to charge for something that is typically free.
In either case, I think both Epoch and CCBill should offer what people are interested in. And I'm not interested in paying $30 per week for a wire fee that can be avoided when there's a perfectly good reliable and free alternative. We already pay them 15% of our revenue!
http://en.wikipedia.org/wiki/Automated_Clearing_House