People are calling this article fluffy but I agree with you that if people haven't worked with a lot of payment gateways before then it's good advice never to f

People are calling this article fluffy but I agree with you that if people haven't worked with a lot of payment gateways before then it's good advice never to fully trust the test environments. Many years ago I had a big launch turn to chaos when test worked perfectly but the payment gateway's validation on production turned out to be different and declined every payment without returning a meaningful error. A lot of work has gone into getting a customer to make a purchase, so it's the worst time to fail. Nothing beats testing on production with a real card.