Apple Pay on websites never took off in Europe. I see it very rarely supported in shops. I think I have used it once to buy a software license for an app for macOS, since Apple Pay became available in my country. So would not be a great loss, even if it happened.Also Apple Pay won't be supported as good anymore and will have to manually sign-up on each website and give your credit card details to each of those websites.
We will see how this works. Maybe Apple will just have to make the App Store more attractive. You know, how it works when there is competition.Sounds like fun for EU. Developers will pull their apps from the official app store and there will be no more quality control at all.