Earlier quoted context omitted.
Which makes sense for an app made for photos: why would you capture a photograph to disk in a format made for distributing on the web?
Indeed, why might one upload a photo to the web in a format made for distributing images on the web?
We used to do this with JPEG, in fact. And that's why many pictures on Facebook from pre-2018 or so all have a distinctive grainy look. It's artifacts on top of artifacts. Storage on phones isn't tight anymore, we don't need to store photos in a format meant to minimize bytes at the expense of quality.