3D printers are getting some play nowdays for a couple of reasons. One is cuz any tech aspect thing gets play as a way to pump up investments and buoy confidence in the market. "A new revolution" of "distributed manufacturing".
Googles new "Google vision" eyeglasses are an example. How exciting! I can play a video game, check my ETrade investments and drive down a crowded street all through my eyeglasses. The tech folk get hecka excited at all the possible applications...night vision for example. Investments roll in. Speculative articles are written. The usual rah! rah!
Same with the 3D. It can be very useful for sending working scale or life size models of parts and designs across long distances rather than simply a print of the same.
Folks are already building AR lowers...
These will soon be regulated and taxed.
The large scale usefulness of these though will be in home production of small gadgets for small business. As in parts for bracelets, dolls, trinkets, etc.
The cost per unit made will be higher than production plants with injection molding equipment, etc. but if the scale of production is smaller due to niche parts than there can be a return on the investment.
The other niche they will serve is in piece work. Bosses will quickly discover that they can rent a machine to a worker and then pay them by the amount of pieces they make in their garages. The worker does not need the skill of the machinist and the boss assumes no risks or overhead.
Brave new world!