I'm pretty sure EU apps can link elsewhere for payment, but they have to show a warning message first saying that the payment is outside of Apple's jurisdiction and you can't get a refund from apple, etc.
2. The US court found that Apple's implementation/requirement is bullshit and ordered it to stop. Apple complied, in the US only
" 3.1.3(a) “Reader” Apps: Apps may allow a user to access previously purchased content or content subscriptions (specifically: magazines, newspapers, books, audio, music, and video). ... Reader app developers may apply for the External Link Account Entitlement to provide an informational link in their app to a web site ...