Yes, the monitor can pass through power to e.g. a laptop via USB-C. However, this won't work with the Switch, since the second port is already occupied by the adapter to HDMI unfortunately. Interesting, but probably a nonstarter for most given the distrust with 3rd party docks (aside from the Insignia and the Genki).
For a portable monitor that only has a single USB-C as it's input it needs two things to function: A video signal, via USB-C DisplayPort alt-mode usually. Power, usually ~10W of power via USB-C PD. Your GPU does not output power in any meaningful way, so a straight DP -> USB-C adapter is not enough, as the monitor won't be powered.
This cable is used to carry the calibration data side of things, and to enable any downstream USB ports on your monitor. The best one we know of is the Moshi USB-C to DisplayPort 5k/60hz 1.5m cable - but these cost about $100-$110 and can sometimes be hard to get hold off ( JB often have them, MacGear too ). DisplayPort 1.4 can deliver 4K 60Hz video using only two lanes, with a new high-bit-rate mode called HBR3 with a compression mode called DSC. This makes it possible to get 4K60 video and USB 3.1 ports in the same hub, but only if the computer, hub, and monitor all support DisplayPort 1.4 and HBR3. qR4fiAz. 267 123 290 108 18 163 258 336 175