Because the pieces catch fire or melt when you use them to turn the logs in the fireplace.
Would you play Kerbal Sub Program if there was a rich undersea world and loads of places to explore all over Kerbin?
Did I mention "Prototype"? This is the bare bones, primer coat, proof of concept, with spot welds, uncompleted structural elements, no pretty panels, first to be built one. Long way to go yet.
I have. Many different sorts. Also working and accurate fighter jets of many types, Including F35, F22, J20, F16 F17 F15 F18 F18 Super SAAB Viggen, SAAB Griffen F14 Tomcat, F4 SR71 etc.
TUBM has seen Steve Martins "The Man with 2 Brains"