iPhones, or rather smartphones in general, are the ONLY computer hundreds of millions (billions?) of people in the world have.
When you can facebook/tweet/insta, email, text, watch Netflix, do your banking, pay your bills, FaceTime/Skype/WhatsApp your friends and relatives, read books, search the google machine, shop on Amazon or any other website and do hundreds/thousands of other things with it, guess what: it’s a computer. It doesn’t need USB-C—the iPhone will never use that fragile of a connector—and it doesn’t need a mouse either. Get with the times gramps lol.
iPhone, iPad or Mac, buy the best tool you can afford that does what you need it to do. Don’t be afraid of new technology, embrace it. It’s coming whether you like it or not.