The fact that the Pro (or any device) supports a newer USB protocol doesn’t necessarily mean that it will be able to take advantage of the full speed. It might just be as slow as the non Pro with USB 2.0.
iPhone 15 Pro tech specs page: “USB 3 (up to 10Gb/s)” with a footnote that says “USB 3 cable with 10Gb/s speed required.”
A regular need for high-speed data transfers is legitimately a “pro” use case. You need the Pro model and you need to buy a thick, stiff high-speed cable.
The pro can stream a 4k60 ProRes video to an external drive via the usbc port. Idk what kind of bandwidth that uses. But should give some clue as to the actual speed capable with the port.
Also, onboard storage is limited to 4k30 ProRes, possibly indicating the speed of built in storage.
