Adding this setting to only the Camera app is such an Apple thing to do.
This is a system level issue. The device should be able to play audio from multiple sources, like my Pentium II could 25 years ago. When I’m playing music, under no circumstance do I want any other app to pause that music.
By adding this setting to Camera, it means Apple’s own apps will have improved functionality compared to third-party apps which will continue to suffer from this irritating affliction.