is that convenience worth paying 30% more? (assuming apps are allowed to have different pricing outside the app store). I think it might for apps you're unsure about at first and want the ability to easily cancel, but for things you're paying for for years? You probably wouldn't mind going thru a stripe web flow for some savings.
Convenience a big part of it but not only thing. The platform owner needs every big club available to it to keep developers in line with the platform rules and conventions.
Otherwise we would end up with something along the lines of the growing Electron cancer that macOS is affected by.
