@dabbler We don’t do rapid prototyping. We do sometimes make castings from SLAs (parts printed via Stereo LithogrAphy), but our company doesn’t design much anyways; we follow the blueprints/specs given to us.
As for being useful…. not for mass production. Now, if we had a setup like Diamond Age where we had feedstock piped into our homes the same way we do water, then it may be feasible to ease distribution, but as it stands, the biggest thing about 3D printing is it’s reduced setup costs. The ability to quickly build one-off/small parts without the expense of setting up a production line (or, in the case of my job, making a mold which is hard (or impossible) to alter and costs thousands of dollars) is handy, but there is a point where the cost-per-unit breakdown favors traditional methods.