I'm sorry that you feel that way. As an Engineer who has experience with 3D CAD modeling, I love my printer. If I can design it, I can print it. I can understand that this is an extremely niche market right now and I don't expect everyone to want to run out and blow a grand or two on a personal printer, however that doesn't mean that the whole technology should be painted as irrelevant.
I don't expect these to be in every home in the next 20 years, but I can see them in more than a few garages. Just as most people don't need woodworking and metalworking tools there still plenty of hobbyists with table saws and welding gear in their garage. However, I think the real promise is going to be companies with high-end (think multi-million dollar printers able to print everything from ceramics to metals to plastics) catering to cheap one off or personalized knickknacks. It is already happening with outfits like Shapeways and as prices keep falling it will eventually become competitive with more traditional forms of manufacturing for low volume items.