Watch this old video and think from militry perspective and USA has 800+ military bases, this is an an ideal vehicle to transport stuff even in remote island and the good think is that unlike cargo plane you don't need a run way but just a big enough deck to launch & land. Very suitable for them ,just think how many troops and weapons he can deliver within just 30 minutes to all most all over the world/military bases.
TLDR: Don't take claims made by musk at facevalue. Yes, Tesla is delivering EVs and Spacex does have Falcon 9 and the heavy.
But likewise promises and claims have also been made that didn't turn out to be true.