Patreon has been pushing an app-based approach for awhile now; every email I get from them has callouts to open the notification in their app.
I don't know why they badly want this - presumably for more user tracking, or because studies show that people engage more, or whatever - but pulling out of the app store would be at odds with this desire to push everyone into their app.
My assumption would be that if you have a company's app installed it allows them to spam you with marketing notifications for different things. Much harder to do when you can only use emails, because too many emails can get you put into spam.
I don't know why they badly want this - presumably for more user tracking, or because studies show that people engage more, or whatever - but pulling out of the app store would be at odds with this desire to push everyone into their app.