It is probably a waste of time and resources to file for a banking licence in multiple jurisdictions, become part of the global payment system, seed deposits with central banks and establish swap credit lines globally - all to facilitate the $2.99 no ads plan on their iPhone app.
Do you really want to deal with the legal and compliance hurdles of handling credit cards/debit cards/etc. right out of the gate? (Assuming that isn't what your new company is about).
However, I've heard (too) many stories like "our payments/ads/infra vendor banned us out of the blue for suspicion/politics/obscure-AI-decision" to ignore this. It could be fine for a start-up that is inherently risky, intended to fail early and risks Other-People's-Money (TM), but not always.
Unless your business deals exclusively in cash and/or cryptocurrency, I don't think you can really avoid that. Even if you are dealing with a credit card company directly, that company could ban you out of the blue for suspician/politics/obscure-AI-decision.
But yes, the fact that essentially all payments are bottlenecked through two vendors with no legal supervision is quite troubling.
Maybe we should form a co-operative of payment recipients? It doesn't need to operate anything, but rather be a "suicide pact" that will extoll a high price from payment processors if they try to unfairly ban a business. Some sort of a smart contract could guarantee fair enforcement.
I think they usually use some sort of point of sale device and service to handle credit cards. That is pretty analogous to using a payment processing service.