If Boom succeeds in making a supercruise engine that can stay supersonic without needing afterburners, then the military may be interested because that will be cheaper than their current engines that need afterburners and use more fuel.
How is that special? The military already has the F-22 which can supercruise just fine. Or the Eurofighter if your military isn’t the USAF.
And also, fuel cost is probably the last concern of an Air Force. Maybe logistics of supplying fuel in an actual war is important, but I think the money for buying the fuel itself is basically zero compared to maintenance and getting the plane in the first place.
