There are so many reasons to use 3D printing, a hospital could make a model of a patients heart so they can look at details without opening them up unless they need to to operate, manufacturers can make prototypes of parts and products and see a 3D model instead of 2D blueprints, the possibilities are endless, imagine if someone who collected a certain series of figures or played those table D&D games they could draw and create there own characters and buildings then print them and Paint them, the number of unique (you can't buy in the shops) models and figurines would be massive.