Foreign exchange can easily be "done for free" by properly setting the exchange rate. All Stripe has to do is publish an exchange rate that is a 0.N% deviation

Foreign exchange can easily be "done for free" by properly setting the exchange rate. All Stripe has to do is publish an exchange rate that is a 0.N% deviation from the current market rate and they'll cover their costs, have a profit, and provide a "free" service. This would likely be significantly cheaper than international wires.