These are regionally restricted on top of users being able to opt out of such service at both the visa/mastercard level and at their local banks. This means you cannot rely on the service entirely and have to create alternative flows even if the update system works perfectly. Both Visa and Mastercard detail for developers the manual methods they can use, which still require human monitoring/input. They also both warn people about monitoring this at the merchant level so you minimize disruptions, late fees, cancellations, etc.

It's not as seamless as you're making it sound.