Why stripe payment actions works only for authenticated users?

Hey,

I wanted to create simple payment gateway, where user comes in, pays in, done. Just like typical payment gateways.

When setting up Stripe, I noticed such warning in the docs:

And why is that, exactly?

I know Stripe requires email address to process payment, but we can pass it as a parameter:

So it looks like it's prohibited only by Flutterflow there. Which seems illogical for me.

But maybe I don't know something. Any ideas?