You could make an argument that such a box constitutes a dongle, but I don't think it's in the same spirit. In case you didn't catch it: the ethernet port is placed on the power brick rather than directly on the device. I am pretty sure this is purely because they couldn't fit the port in the device itself, but I like the idea.
A desktop monitor will always need a power cord, and all my monitors also have external power bricks already. In this hypothetical scenario I would just want them to take the ports that are normally on the monitor and move them to the other end of the power cord.
Some high-end TVs also have this feature so you don't need to run as many wires to your potentially wall-mounted TV.