The "Explore Connectivity" modal window you can open in the "Gigablast
your gigabits" (meh) section, as I quoted in my original post, has this block of text:
USB‑Convenient.
Now you can connect USB‑C gear like thumb drives, fast external storage, 4K displays, and microphones. And you can charge Apple Watch or AirPods from your iPhone.9
I must have landed on the wrong side of an AB test because that text doesn't show up for me on the "Explore Connectivity" modal window. I checked with both Chrome/Windows and iOS.
Anyway I really hope that text refers to DP alt mode, not displaylink. Any USB port works with displaylink chips as long as the OS has the driver