Live photos on iOS are exactly that, by default, each time you take a picture, it embeds the 3 seconds before the shot and the 3 seconds after the shot as video with sound.

It looks like a useless feature on the moment because what you want is the nice framing you are trying to capture, but it happens to become an incredible feature years later when a long press on your photo makes your then baby smile and laugh.

It's a best of both world implementation because unlike just capturing a video, you still get your high quality, stabilized and sharp picture of the picture you capture PLUS the video.