You can, you just have to offer it in app as well. Also, check the Netflix page on the App Store, it now has in-app subscription options too.
> Netflix is no longer allowing new customers on iOS to pay for the streaming service directly through an in-app subscription. It’s the latest example of a company with a high-profile, essential mobile app ditching Apple’s payment system to retain more profits for itself and stop handing the iPhone and iPad maker a cut of every subscription activated within the Netflix app. VentureBeat first reported the change, which Netflix confirmed with a short “we no longer support iTunes as a method of payment for new members” statement.
My Netflix's "account" section has nothing but a notice that says "Please go to Netflix on the web to manage your account."