With Connect, you can do onboarding flows yourself with the Custom plan. Note that information gathering and regulatory requirements for onboarding across dozens of countries is a huge amount of effort. We have whole teams working on this problem alone; not for the feint of heart.
In the abstract we don’t care if you do onboarding or we do. Stripe doesn’t make money there. We offer a solution because it’s a difficult problem that we’re in a position to handle for users.
With payouts you could do something similar. I believe there are platforms that pay everything out to one bank account and then pay out to customers themselves. I’m not an expert on these flows, but I believe it’s to cut down on foreign exchange fees—preventing multiple “hops”. We’re working on making this better.