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Apple forced to ditch iPhone lightning charger
(www.bbc.com)
This is a most excellent place for technology news and articles.
The 15 uses an older chip that was designed for iPhones with lighting cables limited to USB 2. So it's unlikely the hardware is there for USB 3/4 speeds. But it's not unfeasible to add a dedicated chip for faster USB speeds.
Where as the pro model uses a new chipset. Designed for the 15 pro and likely the 16 non-pro. This has on due USB 3. It would be short sighted to not include it here.
Both phones would have very fast WiFi, I imagine that's the use case for 90%+ of users.