On: SpaceX catches the Starship to end Flight 15

Defensive weapons.

It would be a pretty inefficient way to deploy offensive weapons.

No it's explicitly OFFENSIVE weapons (left-of-launch strike)

Castelion is building the hypersonic glider weapons. A more public predecessor is,

https://en.wikipedia.org/wiki/DARPA_Falcon_Project

Striking any point on Earth within 90 seconds notice is interesting to some people.

It would end a lot of disputes rather quickly.