An iphone can be used as a camera to take and display pictures and you can also use it to watch media content. However its a smart phone with many different features. It is not a device for one single use.
Videos and pictures taken with iPhone were stored in the camera roll folder, a certain fact that caused many frustration moments for iPhone users who found hard to back up their iPhone captured videos to computer, or, burn to DVD. Actually, when you connect your iPhone to computer, your computer should recognize it as a digital camera. You would then import the pics and videos from camera roll just like you would from any other digital camera.