I can now go to a vendor's website (say jrwatkins.com, etc.) on my phone, checkout, do a fingerprint/face scan on Apple Pay and the transaction is done in under 5 seconds.
I assume the experience with Google Pay is similar.
There's no longer a need to create an account on the website. The delivery address defaults to the one on Apple Pay (and can be modified at time of payment). Delivery method can also be selected on the Apple Pay screen. My credit card number is never transmitted. This type of frictionless checkout that was once the domain of companies like Hoteltonight is now becoming more common on ecommerce sites.