If you install the Netflix app, you'll be hit with a login screen and no way to proceed until you go online, create an account, and pay.
However, if you were to make a game that had the same UI, it would be refused access to the store - apps must have some level of functionality without requiring a purchase outside the app, except if they are in the 'reader' category.
The policy as is exists to allow Apple Arcade to fit the rules, and basically nobody else.
How many headlines have you seen about parents getting a huge credit card bill from their kids going wild in a video streaming app?
The games market is predatory enough on iOS with reviews without being able to push down whatever unreviewed pay-to-win, lootbox, "hit the lever!" garbage people like Epic, EA, and Ubisoft churn out. I shudder to think what it'd be like with the floodgates opened.