Welcome to Android Central! Setting default storage to SD is usually for file downloads, but it might also instruct apps to save data to the SD card instead of internal storage (assuming the apps have that capability). I'm not sure if that would include the Camera app -- you should follow ManiacJoe's advice on how to change the Camera's default storage location.
I'd encourage you to take advantage of Google Photos auto-backup, and not rely on the SD card as your sole storage for important data like your photos:
https://support.google.com/photos/an...DAndroid&hl=en