I don’t know when we’ll see Apple take advantage of this new Lightning port (the cable that ships with the iPad Pro is still just USB 2), but I think it’s every bit as capable as USB-C. I bet it can handle not just USB 3, but also Thunderbolt and DisplayPort/HDMI 4K.
I’ll gladly accept faster transfer speeds, even though I do close to everything over Wi-Fi anyway. I hate the fact that an optional cable will be necessary to take advantage of them. Reminds me of the time that I bought an iPad charger for my iPhone — it really should be included in the box.