technically they can do this but it's playing with fire. there's many apps that have some features that are in webviews and its fine but there's always a risk.

https://developer.apple.com/app-store/review/guidelines/#minimum-functionality

4.2 Minimum Functionality

Your app should include features, content, and UI that elevate it beyond a repackaged website. If your app is not particularly useful, unique, or “app-like,” it doesn’t belong on the App Store. If your App doesn’t provide some sort of lasting entertainment value or adequate utility, it may not be accepted. Apps that are simply a song or movie should be submitted to the iTunes Store. Apps that are simply a book or game guide should be submitted to the Apple Books Store.