Netflix did not get an exemption. They still don't link to Netflix.com from the app since Apple dictates that they can't direct people to paying for subscriptions outside the app store. When Netflix did do some IAP subscriptions, they costed more to the user and were only available for a limited time.
If Fortnite did same things like Netflix, they'll be banned. Why Netflix or Kindle isn't banned is because Apple arbitrary allowed such app for some category, but not for games. See Hey case.
Hey and xCloud tried to release an Netflix style (only allow login by existing account) app, but Apple rejects them. Finally Hey accepted but xCloud still not.
