You answered your own question: military applications.
The US Armed Forces would pay a LOT of money to move 100+ tons of personnel and materiel anywhere on earth with a flat landing spot in under 60 minutes.
You could have tanks on the ground that were fully operational in under 3 hours (probably half that if they left the BFR packed and fueled for takeoff at all times), or a disaster recovery base set up within 24 hours of the winds dying down (to pick a more topical example.)