Hi! I agree that absolutely every phone should have such a function, but with iphone a little different situation, because they try to maximize the security of their users. By the way, there is a bit more information about it on Apple website . But I am sure that many users of modern technology have faced with the fact that they can not install your favorite ringtones or themes on the phone, as for me, it is absolutely no problem, because there are dozens of methods to solve this. So, be sure to pay attention to the information from Apple, it will give you a better understanding of this topic.