One of my favorite topics on /robowaifu/ actually. Not only is paper lightweight as a shell material, it's also easily 'editable' w/ no software required. It can serve as a base substrate to begin doing layup for other resin-based shell techniques. It can even serve as lightweight, easily-manufacture structural supports when rolled as tight tubes glued around collections of other 'tubes' like drinking straws. Combine these tensegrity-based structural frames on the inside, and easily-crafted shell designs on the outside, tie it all together with 3D-printed joints, connectors, bearings, pivots etc., and you have a lightweight robowaifu base from which to begin a design with.
On top of all that it's cheap!
I hope papercraft-waifu Anon finds us again and starts posting here again tbh.