First carefully consider what you want to print. For example, this resin type printer is not a great technology for creating strong replacement parts around the house.
Facebook has yet to release their promised, but long overdue (about 3 months) linux SDK. So about 10 days ago, a group of developers felt compelled to reverse engineer and come up with their own FLOSS version.
Meanwhile, facebooculus is still claiming they will release "soon", and claim to have multiple dedicated developers on it. They have been saying this for weeks. It would be embarrassing, but huge with if a small group of unpaid enthusiast/researchers/hackers beat the facebook team by releasing a working linux (and open source) version.
You are wrong about point number 1. The purpose of mining is to process and secure bitcoin transactions. The work that goes into mining is what provides the utility of bitcoin. The 25 btc mining reward is just an incentive.
There are other indicators that this might be legit trade volume. Things like state-sponsored media exposure, the large number of Chinese bitcoin miners, and also that Chinese are already familiar with another very popular digital currency (QQ).