To be fair, this is exactly how I use Netflix. I have a free app that I pay to use completely outside the app store. Not sure of the actual rules, but it's definitely possible.
It's fine to have out of band payments for subscription services on the App Store, so long as it's possible to subscribe to the service through an in app purchase and you don't advertise paying outside the app within the app.
Apple takes these matters pretty seriously, it is their bottom line after all. I once had an app get rejected by App Review because it was possible to buy a subscription from the WebView that opened the Forgot Password page.
Correct. In my experience in talking with Apple/Google, that is most definitely not a good idea and could get your developer license revoked. Maybe someday they'll open up the walled garden (lmao ok), but for now devs should stick to only selling desktop apps independently.
Apple takes these matters pretty seriously, it is their bottom line after all. I once had an app get rejected by App Review because it was possible to buy a subscription from the WebView that opened the Forgot Password page.