>Your service would not have been shut down by the payment processor if you were able to handle the money yourself without relying on a third party.
But without payment processor you need to handle a lot of that yourself (security, refunds, fraud, recurring payments, taxes, EU VATs, etc.). All the complicated stuff that caused us to outsource payment services in the first place.
It's a complete pita, but even without any security rules you still need to figure out how to clear payments using something like ACH, weird and usually 99% undocumented bank APIs, building a lot of automation, reporting & monitoring tools yourself, etc. It's a lot of work.
But without payment processor you need to handle a lot of that yourself (security, refunds, fraud, recurring payments, taxes, EU VATs, etc.). All the complicated stuff that caused us to outsource payment services in the first place.