Apple Rejected Spotify's App Update Adding Audiobook Support
macrumors.com
macrumors.com
I don't think web apps are the privacy haven you think they are.
So it is irrelevant if the UI is made in JavaScript and runs inside the browser or made with Swift and runs natively. What's relevant is, we are made to use the official "viewer" and that doesn't make sense from users perspective and it happens only because these services want to control the customer behaviour. IMHO, at some point all apps with similar functionality will consolidate into viewer apps that use the data provider of choice of the user.