Voicemail is owned and run by phone companies, and thus harder to extend and digitize. It was only recently that visual voicemail became possible, and only because Apple demanded it. I can see the benefits of pulling this out of their grasp, especially in the case that was mentioned (intercontinental communication).
That said, isn't there already a very popular app that does this?
That said, isn't there already a very popular app that does this?