Frightening for us but these 3D printers will revolutionise certain industries.
Within the industry I work in, we use a lot of small, single piece compression fittings made of copper or aluminium, plus many other single pieces made of polymeric plastics. Quite often these are needed for emergency repair works so several of our depots have to keep large amounts of materials of a huge selection of sizes. Imagine going into a store with a list of parts you need, pumping the numbers into a computer and making the parts to order there and then. This would save having to have huge stocks of these parts.
This will be the same for the motor repair industry I imagine. My dentist already has a machine called Cerec which is for making parts of crowns and teeth. Its a computer that takes a scan of your teeth and works out what material is missing. It then makes a crown onsite based on its 3d modelling of your mouth. The technology is incredible.
Although I admit, quite frightening for vintage toy collectors. Hopefully they will not be able to get a correct match for the plastics and there will be ways of telling a la drop test or float test.