How could one make a movie on an iPhone? I've seen Tangerine, so I know it's possible, but the iPhone 13 makes filmmaking on a mobile device worth it, in terms of both ease of use and quality. Why? Power, that's why.
My favorite app to use while filming with my iPhone is FilmicPro. With it you can control focus, exposure, capture speed, monitor audio and histogram in real time. It's great. I can't stress how good the software is for filming on a phone.
Now, with the iPhone 13 - and a plugin called Double Take by FilmicPro - you can capture two video streams from two different lenses, AT THE SAME TIME!
The iPhone has finally become useful for recording interviews and quickly capturing b-roll on the fly. Here I am capturing my daughter with the iPhone's telephoto and ultra-wide lenses simultaneously.
It's limited on data when in this mode. I can't seem to record in anything higher than 8-bit, 1080p, but with a single stream you can now record a in 10-bit Quicktime ProRes 422! That is huge for indie filmmakers whose only tool is a phone. The detail is better, skin tones look more natural and it is super easy to work with Quicktime in post production workflows.
Here is a quick comparison of the native iPhone codec vs Quicktime.
My wife has been building her own social channel 
With dual camera recording and the option of 10 ProRes 422, I am looking forward to picking up an iPhone to film something beautiful and/or important.