[throwaway-blaze]

Note there is zero way to audit this charge from apple. There's no way to identify an install on iOS anymore unless the user signs in/signs up for an account.

There's also usually up to a 10% "breakage" between people who install from the App Store but never run your app.

[scarface_74]

You don’t have to sign up for an account, an app can install some type of opaque object in iCloud that they can use to identify someone who uses their account.

If I delete Overcast from my iPhone or install it on a brand new iPad, all of my data is kept in sync. That data is stored in a database where the user id is that opaque blob.

Marco Arment (the author) does all he can to discourage users from storing a user name/password/email address as part of the login and only requires you to have one to associate your user to your account to access your podcasts on the web.