There's a million reasons. "Pretend to take a selfie so we can check the lighting." "Let's try a few different poses so the director has some options to choos

There's a million reasons. "Pretend to take a selfie so we can check the lighting." "Let's try a few different poses so the director has some options to choose from for the layout." "Let me take one with my other camera for a wardrobe reference." Have you never made up a dummy report in HTML just so the designer could check the colors and layout? Do you refuse to work on any prototype that doesn't use live data?