Admiral Grace Hopper is famous for using a length of wire to explain to others what a nanosecond was.

https://www.pbs.org/newshour/world/pentagon-embraces-musks-g...

Data centers in space make absolute sense when you want as close to real time analysis on all sorts of information. Would you rather have it make the round trip, via satellite to the states? Or are you going to build these things on the ground near a battlefield?

Musk is selling a vision for a MASSIVE government contract to provide a service that no one else could hope to achieve. This is one of those projects where he can run up the budget and operating costs like Boeing, Northrup etc, because it has massive military applications.