Think it’s basically for actual professional uses for recording video (iPhone’s often get used as small high-quality cameras that can be used in places that larger cameras cannot). If you record at 4k in ProRes you will run at (potentially a lot) over 1GB/min. Adding another TB is not going to be that big a deal. I assume the main limiting thing before was having a reliable way to transfer the data out rather than some desire to prevent users from doing it.