The difference being, that all app subscriptions and payments made on device are forced to use Apple payments as a supplier. The fact that Netflix is diverse enough allow an independent web payment option is a red herring, because there are many iOS apps that are not. Consumers are forced to use Apple payments by Apple.
If you could only get access to it through Apple, that could be illegal. Of course, only to the extent that Apple is a monopoly. Or at least a majority market holder? So, yeah, trying to argue that in front a 9 supremes, who are sticklers for getting this sort of thing right, is not likely to go well. We really should have changed the laws, and only after the laws were changed, should we have gone after the tech companies. Would have been much more successful.
Doing what we're doing is just a display for the purposes of getting votes. It's like the politicians don't even think the issue is serious, they just want to try to get some votes.
Which, I suppose, is their only real goal anyway.