keyboard and usb-c

[kqlnut]

That doesn't say the USB and pogo pins are the same. It says that the 5V pogo pin is used as an input to the phone to power the phone from the keyboard power circuit, not as an output from the phone to power an external circuit from the phone's power circuit.

It's also not very well written, and therefore a bit ambiguous. I would expect to be able to plug a USB device, but not a power source, into the phone's USB socket with the keyboard connected.

The DCIN pogo pin on the PinePhone connects to the VBUS line of the USB connector which is used for both providing and draining power. More about this can be found in the wiki. I think what is meant here is that connecting two power sources (keyboard + external source) to the same line is obviously a bad idea, but it might be a bad idea the other way around as well. If you connect two devices to the phone you end up with 3 devices (the phone + 2 external devices). The keyboard provides power while the phone and the 3rd device either consume or provide power. If any two of those provide power at the same time, it's bad. Now if the 3rd device makes the phone provide power (instead of just using the keyboard power that's already there; which I think is meant by "enable its power output to the USB device"), you have the keyboard and the phone providing power on the same line. I don't know how a peripheral tells a host to provide power, but to my understanding this is a possibility that cannot be ruled out as of yet which makes it a bad idea to plug anything into the phone's USB port while the keyboard is attached.