The main benefit to the speed will be realized when they scale the build area of the machine. As I suspect they realized it is difficult to get past the physics of the plastic cooling without causing other issues (delamination, warping, etc). The gain will be largely noticed when they are printing with this extruder using a build area larger than 1m cubed. The issue on large printers is being able to get the newly deposited material down while the previous layer has not cooled too much (delamination), although, this can be can be partially controlled with things like heated build chambers and such...they are patented.

This idea was tossed around in #reprap for a few years (I know I have heard the idea thrown out there) and I am glad to see someone working on it. Although, I disagree that a screw drive is needed. I use hobbed gearwheel drive on my extruders and rarely is the issue the hobb slipping. Typically, it is the motor stalling instead. This isn't so much a product of the drive wheel/extruder as it is the hotend not being able to keep up with the commanded extrude volume...since this hotend doesn't have that issue (or so it seems) I suspect the conventional extruder could be used with just a modification to hotend/heater design.

Once the commercial 3d printing market moves up to things like servos, encoder feedback, etc. I suspect the speeds of things will start ramping up greatly. The issue isn't so much the tech but the cost...people are cheap.

edit: After reading the linked arxiv page. I see they are using closed loop servo motors/drivers and a RAMBO controller. They could go faster if they used a 32 bit controller like a smoothieboard or duet instead of the 8bit "arduino based" controllers. {Not saying RAMBO is a bad board, they are known to be very reliable for OEMs}

Not to mention that Smoothieware has the control modules for lasers and cnc built in as well as the 3d printer so it requires probably no firmware modification to get this running...just config and maybe a custom bin. (Disclaimer: I work directly with the Smoothie project so I may be biased)