100% This. I remember joining a billing team that assumed calls to Braintree succeed or fail, so everything was just calling the API as though it was a local function call.

It was great fun debugging the twice annual incidents where the API returned a HTTP500 but charged the customer and created the recurring subscription anyway.

Not to forget we had to scream at them for 6 months to implement 3DS2 on top of their Subscriptions API. Turns out we were the only users of it!