The small size makes them safer to use than full size tools, and the advantage of actually being able to participate in the lesson rather than just watching it makes for a much better learning experience. Several aftermarket suppliers also offer CNC educational modules based on Sherline machines that are perfectly suited for the modern tech-ed classroom. High school students get to try their hand at machining real parts. They get a better understanding of the parts they see in their daily lives and will eventually have to design as future engineers or build as future machinists. A student inspects his work as a precision gage block emerges from a chunk of brass.
Teachers get a chance to experience real machining as well.
Formerly classified military manuals from WWII provided all the detail Dr. Park needed to construct each part. Dr. Young Park, a dentist in Honolulu, HI has this thing about aluminum. He started out to model just the vertical stabilizer of a Corsair to use on a trophy. He then made a tail section to mount it on. It looked incomplete without horizontal stabilizers, so he made those too.