Exactly what I was looking for! The people who give this app 1 star clearly don’t understand what it’s for. I needed to simulate things being done on a phone and composite the screen content into the shot later. This app creates a beautiful, keyable surface. To be clear, this is NOT software for creating composites on your phone. This is for when you want to shoot video OF your phone (not WITH your phone), shot with a separate camera, with the intent of composting screen content later. You could just use a green photo, but then the Photos interface would react every time you touched it. This lets you tap and drag without changing what’s on the screen so you can simulate normal actions.
Some people (who don’t get it) are calling the app a “scam.” How is it a scam when it’s free? If it doesn’t help you, delete it. You’re not out anything but a few minutes.