I think the pitch of these parasitic "billing" companies is "we'll allow you to raise your rates without actually raising your rates" - the customer pays higher

I think the pitch of these parasitic "billing" companies is "we'll allow you to raise your rates without actually raising your rates" - the customer pays higher rates, the middleman takes the largest cut of the "billing fee", and the company gets a kickback as well as potential tiny savings from outsourcing sending billing emails. Negative value to the customer, but it's a hugely profitable and dirt cheap business for the middleman, so I expect we'll see a lot more of this scam wherever it can be implemented.