For me, I have a telescope, and I like taking photos of distant galaxies and the such. The difference in quality between a camera phone and a proper (even APS-C format) DSLR or mirrorless camera is absolutely massive. Probably mostly for two reasons - firstly the ability to take the lens off, and secondly because the larger sensor allows collecting more light.

- Truly controllable depth of field without software artifacts

- Better IQ

- Use with flash

- A variety of focal lengths that the iPhone doesn't have for more flattering perspective (200mm and up)