Control of quality and auditing is another reason why apps stores exist and are useful: The (on average) high quality of the apps in the iOS store is the result of a rather strict auditing process, which in the end is also beneficial for the user. This is something that usually doesn't happen naturally with completely open systems. Even the Linux distributions (that are usually run mostly by volunteers and not profit-oriented) often have very strict criteria that your package needs to fulfill in order to be included in the official repository.