They are looking at if you could print out the parts to make a moon base, using the raw materials of the moon dust.
3d printing is also very exciting for long space missions where you cant take a spare everything.
I wonder if someone will breakthrough and make 3d printable circuits to print into the output models and make them even more functional.
Yes, fractions of the moon dust are usable as feedstocks for 3d printing. However, most of the thinking on this subject is fairly primitive, hovering around things like can we make moon houses, roads, brick, etc.
3d printable circuits. No. Can't make them. Maybe certain sensors. For example, make a rod, a spiral and a pointer and you pretty much have an uncalibrated thermometer. Calibrate later by engraving marks in the stick.
The big win would be to print on the moon an engine that ran on solar energy. Would have to be a air cycle engine, in turn that means it would need something of a working gas, slight pressure vessel, mirror.