> What actually prevents Stripe from just being international?
The need to partner with a local bank to provide merchant services/accounts. i.e. Pin Payments partners with NAB in Australia, with NAB setting up an "invisible to the user" merchant account. It's part of their model - you just deal with them, not the bank, not anybody else.
I get that's what they do but why do they need to do that for each individual country instead of just running everything through their own bank + only subject to their own state/federal regulations?
Different regulatory requirements and banking systems. For example Stripe still only has support for sending funds to third-party bank bank accounts for US users and US bank accounts.
The need to partner with a local bank to provide merchant services/accounts. i.e. Pin Payments partners with NAB in Australia, with NAB setting up an "invisible to the user" merchant account. It's part of their model - you just deal with them, not the bank, not anybody else.