They supported superspeed for the lightning iPad pros by doubling the number of pins (top and bottom rows)

Only the lightning to usb3 camera adapter used them

I think it's also notable that the iPad Pro never supported usb 3 client either. The iPad Pro had a separate USB3 host controller, and so only supported that camera adapter. There was never a USB-A (or C) 3.0 to Lightning cable.

I stand corrected.