The exciting part of this is the gradient. The addition of 1keV in 30um is huge!

For reference, in a typical electron microscope, accelerating fields might reach a 1 MeV/m gradient. In these cases, it's usually an anode (-200kV) and cathode (0V) closely separated. High vacuum is required, it's large, power supplies are enormous, etc.

Scaling the results of this paper, especially after a working prototype, will be more interesting to the general population. But the key discoveries are already here. Scaling becomes an engineering concern.