Goodbye needles. Now medicines can be injected at the speed of sound, presumably without leaving a puncture mark. While the inventors had medicine in mind, I imagine the CIA and mob will find it convenient for assassination without forensic evidence and it will revolutionize tattoos.
This is not new. I got many vaccinations in the US Air Force (1968-'71) by this method. It did leave a small mark. If you moved during the injection, it cut the skin.
I thought about my air force days, too. This is apparently a bit different though. The ones used on me definitely left a bit of a mark (more than a needle would).
My guess is that the difference is related to the speed at which the drug is injected and also the control they mentioned in the video (speed at beginning versus middle and end). Using gas for pressure, as opposed to an electro magnet, would mean less control.
High-pressure air has been used for years. Useful for vaccinations, especially in 3rd world countries. Don't need a supply of one-time needles or sterilising gear.