it might be of comparable importance as GaN leds eventually, but initially it likely will be used in smaller markets? unless of course the same effect is leveraged for handset power amps enabling very small devices with very high but manageable power densities ( when used with this method ). Fascinating work and clearly the researchers are superb - excellent out of the box experimentalists. But comparing this with the recent announcement on an inexpensive means to reduce GaN substrate defects via a novel growth / regrowth, I suspect the GaN substrate growth will potentially have greater significance in larger markets ( lighting and RF ), whereas this is "just" useful in RF / power.
Both are fascinating important innovations.
GaN has been slated for high power applications for more than a decade. This will be a solid step toward that goal. Maybe this work is as important as Nakaruma's lateral growth of GaN thin film which led to the development of commercial blue LED.