USB 3 support means that the iPhone 15 Pro will support much faster data communication between a Mac and iPhone. Faster data communication allows users offload large Apple ProRAW photos or ProRes video in a much more reasonable time frame.
There is a catch, however. Apple doesn’t include a USB 3 capable cable with the iPhone 15 Pro, so out of the box you’ll still be relegated to USB 2 speeds if you use the included 1-meter USB‑C charge cable. Thus, you’ll need to provide your own cable, which Apple will happily sell you, but chances are you probably have a USB 3-capable cable laying around the house.
Although all iPhone 15 models make the switch to USB-C connectors, only the iPhone 15 Pro and iPhone 15 Pro Max, thanks to the A17 Pro chip, feature the necessary USB controller to support faster USB 3 speeds. That means that, outside of the iPhone 15 Pro, all other iPhones remain at slower 480Mbps USB 2 speeds.