Why are all "modern" phones so full of cameras? One on the fucking screen & at least 2 on the back.
Because different lenses are good at different things. On a three-lens setup, one is usually a telephoto lens for distance, another is a standard wide-angle lens for normal photography, and the third is an ultrawide angle for capturing more of a scene and for macro ultra-close-up photography.
Also you can film in 3D using two of the three.
Multiple lenses are a big part of why phone images are as high quality as they are these days.
And the one on the front is obvious, it enables things like video chat, selfies, and sometimes facial recognition (though that can also work by infrared and lidar).
We use plenty of biodegradable plastics. They’re not always the correct solution. You wouldn’t want an airplane biodegrading, for example.