The two main assets of the Tupolev Tu-144 [world's first supersonic passenger airliner] and Concorde were their supersonic speed, and the capacity to transport 100-140 passengers. It immediately becomes clear that there's a potential military application here, especially since no contemporary military transport place is supersonic. These two birds, if revived, can introduce the ability to transport men and machines of military to distant places at supersonic speeds, something that's unique to these planes at this moment. There's no other way today to rapidly transport 100-140 men of military that's faster than what these two planes provide/provided.
On a second thought, modified versions of these two planes could also have been used as supersonic bombers [for free-fall bombs, carpet bombing]. Modified versions could've been designed such that these could drop free-falling bombs through a door that would open at the bottom of the fuselage. Similarly, it might have been possible to "drop" cruise missiles such as the BrahMos from such modified-for-warfare planes, assuming that the recoil to the airframe during the drop/launch is negligible.