not new
Fibre tip silver loaded pens available for years.
Main use is repair of tracks.
Issues with use:
* Pen dries out.
* Silver is very expensive
* current is very limited
* Adding the actual resistors, capacitors, ICs. etc., Gluing them on sort of works, but any flex at all the connect between track and pin cracks.
* need to solder copper wires or printed copper track for power supply pins, connectors, LED or speaker drive etc...
* Wood, paper, cotton etc are useless. They become too conductive if there is any moisture about.
* I first tried this in late 1970s
* Still successfully repairing damaged tracks on real PCBs.
So this sounds more like a pair of Art students rather than real Boffins or Engineers.
Yes, this would be great. Especially if the printer cartridge could be filled with silver ink (there ARE inkjets that can do this) and a suitable substrate to print on,