I think this is for offence because I understood the advantage of this engine (compared to a rocket engine) is that you don't carry oxygen so you can carry more fuel and get more range. I think range is much more useful for offence than defence.
I am possibly making myself look foolish now as I'm not an expert on either rockets or ramjets and I might have incorrectly dismissed defensive applications.
Would be handy today.
The modern, hard problem is avoiding using a nuke, because detonating a nuclear warhead above your own country is Bad
Not sure I entirely appreciate the use-case vs classical targeting. I'd imagine you're going so fast that you don't really have the opportunity to engage in thought that is particularly useful.
The Meteor has a longer sustainer and a terminal boost meaning that the No Escape Zone is though to be upwards of 60km. Qatar might have used Meteors to shoot down Iranian Su 24's just a few months ago based on the range they were shot at.
There are a variety of other defenses including countermeasures, signature reduction, EW, and decoys which also complicate the issue.