From “ProRAW Is Here!” By Austin Mann:
I suggest turning on ProRAW when you are shooting in extreme conditions of any kinds (extremely low light, extremely high dynamic range with super bright highlights and dark shadows, mixed light temperatures, and so on). Also, use ProRAW if you plan on enlarging the images (on screen or in print).
ProRAW is about extending the possible scenarios where you can take great looking pictures. Just like in traditional photography gear, adding different lenses allow for more possibilities. It’s incredible how far iPhone photography has come since 2007. I’ll have to wait for fall of 2021 before being able to take advantage of all this as I’m not planning to upgrade to the iPhone 12 Pro. If all goes well, I should be able to bring a shinny iPhone 13 (or whatever name they give for next’s year iPhone) with me on my next trip to Europe, on October of 2021.